0:00:06 > 0:00:11This is Gordon Welchman, a World War II codebreaking hero.
0:00:11 > 0:00:15Without him, the top-secret German Enigma codes
0:00:15 > 0:00:17might never have been broken.
0:00:18 > 0:00:20The war could have lasted two more years
0:00:20 > 0:00:23and tens of thousands more would have died.
0:00:26 > 0:00:28Gordon Welchman should be famous.
0:00:30 > 0:00:33His contribution to the war was as great as Alan Turing's.
0:00:35 > 0:00:37Why have we never heard of him?
0:00:38 > 0:00:43When I was a child, there was always, in the family, the sense
0:00:43 > 0:00:45that Dad had done something quite important during the war,
0:00:45 > 0:00:48but, of course, we didn't really know the details
0:00:48 > 0:00:50and it couldn't really be talked about.
0:00:50 > 0:00:54Gordon Welchman was the architect of a codebreaking technique
0:00:54 > 0:00:57that was so clever and so powerful
0:00:57 > 0:01:02that its wartime use at Bletchley Park still remains classified.
0:01:03 > 0:01:07Like Turing, his extraordinary legacy began at Bletchley
0:01:07 > 0:01:09and continues to this day.
0:01:10 > 0:01:14Just as Turing is now celebrated as the genius behind the computers
0:01:14 > 0:01:18that dominate our world, so Welchman's influence
0:01:18 > 0:01:23is everywhere...but until now, it has remained in the shadows.
0:01:23 > 0:01:27His secret work in code-breaking and communications
0:01:27 > 0:01:30had an impact beyond anything he could ever have imagined.
0:01:32 > 0:01:35Only now, with Edward Snowden's recent revelations
0:01:35 > 0:01:40of the extent of global surveillance by GCHQ in Britain and the NSA
0:01:40 > 0:01:45in America, can we understand Gordon Welchman's true legacy.
0:01:46 > 0:01:49It seems to me that...
0:01:49 > 0:01:53some of the things really have been kept secret too long.
0:01:53 > 0:01:57Turing was undone by his private life, but is now
0:01:57 > 0:02:01officially pardoned and celebrated as a genuine British hero.
0:02:01 > 0:02:05But when Gordon Welchman chose to come out of the shadows
0:02:05 > 0:02:09to reveal his secrets, the dark world of espionage was waiting.
0:02:10 > 0:02:14This man, who dared tangle with his own legacy,
0:02:14 > 0:02:16was ultimately destroyed by it.
0:02:26 > 0:02:28September 1939.
0:02:29 > 0:02:32As Britain declared war on Nazi Germany,
0:02:32 > 0:02:35an extraordinary rag-tag army was being assembled
0:02:35 > 0:02:39at Bletchley Park in Buckinghamshire to fight a secret war.
0:02:42 > 0:02:45Their mission was to crack the hardest code ever devised,
0:02:45 > 0:02:48created on a machine called Enigma.
0:02:53 > 0:02:55Enigma lay at the heart of the German armed forces'
0:02:55 > 0:02:57communications system.
0:02:57 > 0:03:01If they could break in, these chess masters, crossword addicts
0:03:01 > 0:03:06and bridge fanatics might just save Britain from the Nazis.
0:03:08 > 0:03:10The best and the brightest were being recruited
0:03:10 > 0:03:12from Britain's top universities.
0:03:15 > 0:03:19Two of this elite were the renowned mathematician Alan Turing,
0:03:19 > 0:03:25and the Dean of Sidney Sussex College, Cambridge, Gordon Welchman.
0:03:25 > 0:03:27Gordon Welchman was actually quite glamorous.
0:03:27 > 0:03:30He was good looking and he knew he was good looking.
0:03:30 > 0:03:32He had a way with the ladies.
0:03:32 > 0:03:34He was fantastically bright,
0:03:34 > 0:03:37very pugnacious, obviously a very proud man.
0:03:38 > 0:03:41He did mountain climbing,
0:03:41 > 0:03:44he did sailing, he loved dancing.
0:03:44 > 0:03:47Here was a man who had clearly been watching Hollywood movies.
0:03:47 > 0:03:50He was kind of Errol Flynn and Robert Donat.
0:03:50 > 0:03:54It's very much that kind of dashing young chap kind of feel to him,
0:03:54 > 0:03:58as opposed to the shambling absent- mindedness of many of his colleagues.
0:04:01 > 0:04:05Welchman was one of the five original elite codebreakers,
0:04:05 > 0:04:08given the impossible task of decoding the Enigma Machine.
0:04:12 > 0:04:14Enigma used a combination of rotors, plug boards
0:04:14 > 0:04:18and wires to put the German messages into secret code.
0:04:20 > 0:04:22The chances of breaking this code
0:04:22 > 0:04:27were one in 159 million million million.
0:04:29 > 0:04:32Welchman was set on a radical approach.
0:04:33 > 0:04:35He ignored the unreadable messages,
0:04:35 > 0:04:38and concentrated instead on what he could read.
0:04:39 > 0:04:44The first few letters and numbers of each message were not in code.
0:04:44 > 0:04:45These were call signs,
0:04:45 > 0:04:49like addresses identifying who the messages were to and from.
0:04:51 > 0:04:54It was a brilliantly simple starting point,
0:04:54 > 0:04:56yet it would prove crucial.
0:05:00 > 0:05:04As I studied that first collection, I began to see, somewhat dimly,
0:05:04 > 0:05:07that I was involved in something very different.
0:05:13 > 0:05:17Welchman started to track these call signs - who was communicating
0:05:17 > 0:05:20with whom, how often, and in which direction.
0:05:22 > 0:05:25They call it chat that comes over the air...
0:05:27 > 0:05:29..and by this means we can build up
0:05:29 > 0:05:32a picture of a German unit
0:05:32 > 0:05:34of the air force, for example,
0:05:34 > 0:05:37the headquarters, any out stations it has,
0:05:37 > 0:05:41and how they keep in touch with each other and send messages.
0:05:45 > 0:05:48We were dealing with an entire communications system
0:05:48 > 0:05:51that would serve the needs of the German forces.
0:05:53 > 0:05:57The call signs came alive as representing those forces
0:05:57 > 0:06:02whose commanders would have to send messages to each other.
0:06:03 > 0:06:06The technique Welchman was using was called traffic analysis.
0:06:08 > 0:06:12It was this simple observation, that a message must include
0:06:12 > 0:06:14details of the sender and the receiver,
0:06:14 > 0:06:18which would allow Welchman to see the entire network of the enemy.
0:06:23 > 0:06:26With this simple insight, modern codebreaking was born.
0:06:28 > 0:06:32And it allowed Welchman to begin unravelling the enemy's secrets
0:06:32 > 0:06:34from hundreds of miles away.
0:06:35 > 0:06:39And they had a big wall map and you could, visually,
0:06:39 > 0:06:43see the whole set-up of the German communications system.
0:06:44 > 0:06:47It was Bletchley's first major breakthrough.
0:06:48 > 0:06:51And it had been achieved without reading a single message.
0:06:53 > 0:06:58Without an analysis of traffic, you would never have been able
0:06:58 > 0:07:02to use cryptography to win the war.
0:07:02 > 0:07:06When you hear phrases like "traffic analysis" or "signals intelligence",
0:07:06 > 0:07:10it doesn't immediately sound quite so glamorous, really.
0:07:10 > 0:07:13I think possibly that's one of the reasons why Gordon Welchman
0:07:13 > 0:07:17hasn't been recognised so much, but if people knew just how absolutely
0:07:17 > 0:07:20he was the kind of the spine of the entire Bletchley Park operation,
0:07:20 > 0:07:23then they would look at him in an completely new way.
0:07:25 > 0:07:28The Enigma codes had still not been broken, but Welchman already
0:07:28 > 0:07:32knew the exact position and strength of thousands of German troops
0:07:32 > 0:07:37and hundreds of aircraft, using the power of traffic analysis.
0:07:37 > 0:07:41He now realised that Bletchley Park could become as forceful
0:07:41 > 0:07:46a part of Britain's defences as the Army, Navy and Air Force.
0:07:47 > 0:07:50Their weapon would be intelligence.
0:07:53 > 0:07:56No-one else seemed to be doing anything about this potential
0:07:56 > 0:08:01gold mine, so I drew up a comprehensive plan,
0:08:01 > 0:08:06which called for the close co-ordination of radio interception,
0:08:06 > 0:08:08analysis of the intercepted traffic...
0:08:10 > 0:08:14..breaking Enigma keys...
0:08:14 > 0:08:16decoding messages on the broken keys,
0:08:16 > 0:08:20and extracting intelligence from the decodes.
0:08:22 > 0:08:25This was still the "phoney war",
0:08:25 > 0:08:28before fighting between Germany and Britain had begun...
0:08:29 > 0:08:32..but Welchman was proposing a total reorganisation
0:08:32 > 0:08:37of Bletchley Park, a radical plan that would require far more people
0:08:37 > 0:08:40than a few tweedy professors solving puzzles.
0:08:41 > 0:08:43Welchman went to his boss.
0:08:46 > 0:08:48He won high-level approval for my plan
0:08:48 > 0:08:51and we were able to start recruiting the high-quality staff
0:08:51 > 0:08:53that would be needed.
0:08:58 > 0:09:01Welchman's creation was called Hut 6,
0:09:01 > 0:09:04a modest name that belied the magnitude
0:09:04 > 0:09:07of just what was achieved within its walls.
0:09:08 > 0:09:11In this modest hut, brilliant people made breakthroughs
0:09:11 > 0:09:14that helped change the course of the war.
0:09:16 > 0:09:20For more than 70 years, it lay derelict, unloved and abandoned,
0:09:20 > 0:09:24until it was painstakingly restored by the Bletchley Park Trust
0:09:24 > 0:09:26to how it would have been in 1940.
0:09:27 > 0:09:31We had two or three or four little lights
0:09:31 > 0:09:36hanging on wires from the ceiling, and we had collapsible chairs
0:09:36 > 0:09:39and tables - not very comfortable -
0:09:39 > 0:09:41and that was our equipment,
0:09:41 > 0:09:45so it really wasn't for a high-powered government machine.
0:09:47 > 0:09:51Jane Fawcett was one of 400 people who worked at Hut 6.
0:09:51 > 0:09:53All were sworn to the utmost secrecy.
0:09:55 > 0:09:57Many took their secrets to their graves.
0:09:59 > 0:10:01Now, only a handful are still alive.
0:10:03 > 0:10:05I was in the Royal Corps of Signals
0:10:05 > 0:10:11before, rather against my will, I was transferred to Bletchley
0:10:11 > 0:10:17and there I was learning to be an interceptor.
0:10:18 > 0:10:22I saw a notice - "Men with suitable qualifications
0:10:22 > 0:10:25"required for transfer to the intelligence corps".
0:10:26 > 0:10:30I was a bit of a romantic and I thought, "Well, you know,
0:10:30 > 0:10:35"I might get involved in some clandestine operations."
0:10:37 > 0:10:39Bletchley scoured the country
0:10:39 > 0:10:42for the right sort of people for top-secret work.
0:10:44 > 0:10:47You have the very posh debutantes...
0:10:49 > 0:10:53..drawn from the higher echelons of society, initially,
0:10:53 > 0:10:56apparently, because it was felt
0:10:56 > 0:10:57that the smarter a girl's family,
0:10:57 > 0:11:00the more likely it was that she'd be able to keep a secret.
0:11:00 > 0:11:01Happy days.
0:11:02 > 0:11:07I did the season, which was where the debutante photographs
0:11:07 > 0:11:12come from, and I regarded that as a complete waste of time and money.
0:11:15 > 0:11:17And then the war broke out.
0:11:19 > 0:11:25I got a letter from one of my best friends, who said,
0:11:25 > 0:11:29"We're terribly busy. We really need you. Could you come and help?"
0:11:35 > 0:11:39As German Panzers raced across Western Europe, Bletchley Park
0:11:39 > 0:11:42at last found a way to read Enigma traffic.
0:11:42 > 0:11:45The intelligence it produced was codenamed Ultra.
0:11:46 > 0:11:50Almost immediately, it gave them a major breakthrough.
0:11:51 > 0:11:5530 years after the war, in the only filmed interview Welchman
0:11:55 > 0:11:58ever gave, he revealed how this intelligence had been turned to
0:11:58 > 0:12:03advantage during the British Forces' retreat from France at Dunkirk.
0:12:04 > 0:12:09In the battle of France, probably the most important thing
0:12:09 > 0:12:13which came out of Ultra, we were still breaking it in,
0:12:13 > 0:12:17was that it was realised so early
0:12:17 > 0:12:20that we were in a hopeless position.
0:12:22 > 0:12:26It showed Hut 6 had been established just in time.
0:12:29 > 0:12:31And it was decided to get out as quick as we could.
0:12:31 > 0:12:38And this meant that there was time to organise the armada
0:12:38 > 0:12:42of small boats that managed to get the troops back out from Dunkirk.
0:12:43 > 0:12:45The immediate success of Hut 6
0:12:45 > 0:12:49was a testament to Welchman's steely-eyed vision.
0:12:49 > 0:12:51You do need this because,
0:12:51 > 0:12:56in an establishment filled with absent-minded boffins who were
0:12:56 > 0:12:59sort of walking into cupboards thinking it's the way out of the
0:12:59 > 0:13:02room or trying to stuff sandwiches into their pipes, you need someone
0:13:02 > 0:13:07with, you know, the clarity of thought of Gordon Welchman.
0:13:07 > 0:13:09Well, I think he was the right person at the right time.
0:13:09 > 0:13:12I think he probably had a lot of personal characteristics that
0:13:12 > 0:13:15were really vital for his work here.
0:13:15 > 0:13:17He doesn't have any time for faffing about.
0:13:17 > 0:13:21There's a war on and he has a very particular idea
0:13:21 > 0:13:23of how this war should be fought.
0:13:26 > 0:13:28By the end of 1940,
0:13:28 > 0:13:32Hut 6 was at the heart of the whole Bletchley Park operation.
0:13:33 > 0:13:36Here, they used traffic analysis to select
0:13:36 > 0:13:40and target particular German radio networks and operators.
0:13:41 > 0:13:43Their traffic was then intercepted
0:13:43 > 0:13:47and decoded, thanks to a remarkable new mechanical device,
0:13:47 > 0:13:51which was helping to break key Enigma signals, on a daily basis.
0:13:53 > 0:13:55It was called the bombe.
0:13:58 > 0:14:01It simulated all the possible rotor configurations
0:14:01 > 0:14:02of the Enigma machine.
0:14:05 > 0:14:09The bombe could check them hundreds of times faster than a human being.
0:14:13 > 0:14:17But it was very limited. To run a test, known as a bombe run,
0:14:17 > 0:14:20it needed to compare a short phrase from the code
0:14:20 > 0:14:24with what the codebreakers guessed might be the original message.
0:14:26 > 0:14:30For example, German messages might begin with the words "Heil Hitler".
0:14:32 > 0:14:34This guessed text was known as a crib.
0:14:34 > 0:14:36If they were right in their guess,
0:14:36 > 0:14:39the bombe could start cracking the code.
0:14:40 > 0:14:42But they needed accurate cribs.
0:14:42 > 0:14:46To find them, Welchman realised the human routines of the German
0:14:46 > 0:14:49operators could be the vulnerable link.
0:14:50 > 0:14:52What Welchman discovered
0:14:52 > 0:14:56was that by understanding the way that the Germans
0:14:56 > 0:15:00used their communications, you could start to predict more easily
0:15:00 > 0:15:03where particular types of message would come.
0:15:03 > 0:15:06There was a German commander in Brittany somewhere
0:15:06 > 0:15:11who. during the war, regularly sent in every morning a message, saying,
0:15:11 > 0:15:15"Alles ist in Ordnung", "Everything is OK here".
0:15:15 > 0:15:18It was the same phrase he used every morning,
0:15:18 > 0:15:23which was a godsend to the decryptors in Hut 6.
0:15:25 > 0:15:28It was a godsend because if they could work out what these
0:15:28 > 0:15:32encoded letters were, they were on their way to cracking the code.
0:15:33 > 0:15:37So cunningly, they targeted specific operators,
0:15:37 > 0:15:40trying to provoke them into using predictable phrases.
0:15:40 > 0:15:42They called it gardening.
0:15:43 > 0:15:46This German officer in Brittany
0:15:46 > 0:15:51used to report, "Lone aircraft approaching".
0:15:53 > 0:15:55So we used to send regularly this aircraft over,
0:15:55 > 0:15:58so he'd send the same message.
0:16:00 > 0:16:04Armed with a crib, the Bletchley team could now start a bombe run,
0:16:04 > 0:16:06and hope to find the Enigma settings.
0:16:08 > 0:16:11But it was a race against time.
0:16:11 > 0:16:13The German codes were changed at midnight...
0:16:18 > 0:16:21..and the bombe might take days to find an answer.
0:16:23 > 0:16:25Even if they cracked the code,
0:16:25 > 0:16:28it would be too late to help the Allies.
0:16:28 > 0:16:31Welchman's genius was to come up with a modification
0:16:31 > 0:16:33of Alan Turing's brilliant design...
0:16:35 > 0:16:38..and make it work many times faster.
0:16:39 > 0:16:40It was Gordon Welchman
0:16:40 > 0:16:43who spots the one thing that the machines
0:16:43 > 0:16:45need that could give them
0:16:45 > 0:16:47an almost uncanny elegance
0:16:47 > 0:16:49and beauty in the way that they worked.
0:16:50 > 0:16:53Welchman came up with an inspired, improvised solution.
0:16:55 > 0:16:58A simple electrical circuit that dramatically improved
0:16:58 > 0:17:01the chances of finding the correct rotor settings.
0:17:04 > 0:17:09It was called the diagonal board. The impact was immediate.
0:17:10 > 0:17:13It reduced bombe runs from days down to hours or even minutes.
0:17:16 > 0:17:18The German codes could be cracked,
0:17:18 > 0:17:22sometimes before they were even read by the intended enemy recipient.
0:17:25 > 0:17:29So here we see an example of Gordon Welchman's fantastic mathematical
0:17:29 > 0:17:33intelligence coming through, easily a match for that of Alan Turing.
0:17:35 > 0:17:39At Dunkirk, Ultra intelligence had proved its worth, snatching
0:17:39 > 0:17:42thousands of British troops from death or certain capture.
0:17:46 > 0:17:51In May 1941, Bletchley Park proved intelligence...
0:17:51 > 0:17:53could also bring victory.
0:17:56 > 0:18:00The main part of our fleet was out pursuing the Bismarck.
0:18:00 > 0:18:03She was the latest German ship
0:18:03 > 0:18:06and the best thing they'd got in the navy and very important.
0:18:08 > 0:18:12The battle cruiser Bismarck was the most feared ship of the German Navy.
0:18:12 > 0:18:18On May 24th 1941, she sank the pride of the British Navy...
0:18:18 > 0:18:22HMS Hood, Britain's most modern and biggest ship.
0:18:28 > 0:18:301,400 British sailors lost their lives.
0:18:33 > 0:18:35Only three of her crew survived.
0:18:37 > 0:18:41Churchill ordered the might of the Royal Navy to hunt Bismarck down.
0:18:43 > 0:18:44But where was she?
0:18:45 > 0:18:48At Bletchley, Welchman's team believed German messages
0:18:48 > 0:18:52might reveal her location.
0:18:52 > 0:18:56Gordon was always in the depths of the deepest thought,
0:18:56 > 0:19:02so he wasn't a very sociable person, as far as I remember, but then
0:19:02 > 0:19:05why should he be? Because he hadn't got time to talk to people like me.
0:19:05 > 0:19:06He was just...
0:19:06 > 0:19:09riding a tremendously important horse
0:19:09 > 0:19:14and trying to get there quicker than it was possible to get there.
0:19:17 > 0:19:21Sifting through the entirety of German naval communications
0:19:21 > 0:19:24for any reference to the Bismarck was a daunting challenge.
0:19:26 > 0:19:30What I had to do was to take the Enigma telegrams
0:19:30 > 0:19:35as they arrived in Hut 6, and I had to put them into the machine.
0:19:35 > 0:19:38Then I had to look at them and see whether - they were all
0:19:38 > 0:19:42in German, of course - see whether they appeared to be of any interest.
0:19:42 > 0:19:46Then, the breakthrough they had been waiting for.
0:19:46 > 0:19:51We discovered this message from a German commander
0:19:51 > 0:19:55to the commander of the Bismarck saying, "Where are you going?
0:19:55 > 0:19:58"I'm worried about my son, who's on board".
0:19:58 > 0:20:02And the message came back, which I got, which said, "Brest."
0:20:02 > 0:20:04At last, they had a location.
0:20:04 > 0:20:06The Bismarck was heading for the port of Brest
0:20:06 > 0:20:10in Northern France, being used by the German Navy.
0:20:12 > 0:20:13A powerful Royal Navy battle group
0:20:13 > 0:20:16was immediately ordered to hunt down the Bismarck.
0:20:17 > 0:20:20NEWSREEL: In this, perhaps the most dramatic naval film ever taken,
0:20:20 > 0:20:22you'll see salvos from the Bismarck
0:20:22 > 0:20:24failing to hit one of our battleships.
0:20:24 > 0:20:26This was during the chase right across the Atlantic,
0:20:26 > 0:20:29when the Nazi ship was running from the guns of our squadron.
0:20:42 > 0:20:47And I was on duty for 24 hours during that period
0:20:47 > 0:20:51without really having anything to eat or certainly no sleep.
0:20:51 > 0:20:54But it was terribly exciting.
0:20:54 > 0:20:56A torpedo dropped from a Swordfish biplane
0:20:56 > 0:20:59disabled the rudder of the Bismarck.
0:20:59 > 0:21:02The British cruisers closed in.
0:21:02 > 0:21:05We were all absolutely on our toes wondering what was going to come
0:21:05 > 0:21:09through next because we knew it was one of the major battles of the War.
0:21:09 > 0:21:12When these pictures were taken during the action,
0:21:12 > 0:21:14the Bismarck was nearing her end.
0:21:14 > 0:21:18It fell to Hut 6 to decode the very last message sent from the Bismarck.
0:21:20 > 0:21:24"Ship unmanageable. We shall fight to the last shell.
0:21:24 > 0:21:25"Long live the Fuhrer."
0:21:27 > 0:21:29And eventually they sank her.
0:21:31 > 0:21:36The flagship of the German Navy went down with over 2,000 of her crew.
0:21:38 > 0:21:40I mean, that was a day to remember.
0:21:40 > 0:21:46We were...constructing a jigsaw but half the pieces were missing.
0:21:46 > 0:21:50Now it all made a picture and the whole jigsaw came together.
0:21:52 > 0:21:55We were invigorated immediately.
0:21:57 > 0:22:00It was Britain's first significant victory
0:22:00 > 0:22:02in the darkest days of World War II.
0:22:03 > 0:22:07Bletchley Park had proved that intelligence could sink ships.
0:22:10 > 0:22:14Yet Welchman knew that they were chronically under-resourced,
0:22:14 > 0:22:18still a cottage industry and they could achieve so much more.
0:22:19 > 0:22:22The staff and the bombes were working around the clock,
0:22:22 > 0:22:25but vital intelligence was not being picked up in time.
0:22:26 > 0:22:30Welchman realised that he had no choice but to go to the very top.
0:22:32 > 0:22:35He, together with Alan Turing and Stuart Milner-Barry, wrote
0:22:35 > 0:22:40this fantastically audacious, rather cheeky message to Winston Churchill.
0:22:40 > 0:22:43Gordon put a lot of pressure on Churchill to produce more staff
0:22:43 > 0:22:47for us because he realised that we were grossly over-worked
0:22:47 > 0:22:52and under considerable strain and that our equipment was appalling.
0:22:54 > 0:22:58Now, imagine writing a letter like this to Winston Churchill.
0:22:58 > 0:22:59"Dear Prime Minister,
0:22:59 > 0:23:03"some weeks ago you paid us the honour of a visit
0:23:03 > 0:23:06"and we believe that you regard our work as important.
0:23:06 > 0:23:11"We think, however, that you ought to know that this work is being held up,
0:23:11 > 0:23:13"and in some cases is not being done at all,
0:23:13 > 0:23:18"principally because we cannot get sufficient staff to deal with it."
0:23:18 > 0:23:22This has got Gordon Welchman all over it. Just go direct to the top man.
0:23:22 > 0:23:24And that's exactly what Gordon Welchman did
0:23:24 > 0:23:27and he got an instant reply.
0:23:27 > 0:23:31"Make sure they have all they want on extreme priority
0:23:31 > 0:23:36"and report to me that this has been done. Action this day."
0:23:37 > 0:23:39This memo had a remarkable effect.
0:23:41 > 0:23:43Bletchley did indeed receive more resources.
0:23:44 > 0:23:46Major building work followed.
0:23:48 > 0:23:52The park was transformed from a ramshackle collection of huts
0:23:52 > 0:23:55into a giant code-breaking production line.
0:23:58 > 0:24:01Now, 70 years later, this is what remains of it.
0:24:03 > 0:24:06Hut 6 moved from their draughty wooden shed
0:24:06 > 0:24:09into this huge brick building.
0:24:10 > 0:24:13Thousands of people worked here around the clock
0:24:13 > 0:24:15and in conditions of absolute secrecy,
0:24:15 > 0:24:19breaking into supposedly unbreakable German messages.
0:24:21 > 0:24:23It represented a remarkable recognition
0:24:23 > 0:24:26of the power of codebreaking in the war effort.
0:24:42 > 0:24:45Two bombes became 200.
0:24:47 > 0:24:50The population of Bletchley Park steadily rose
0:24:50 > 0:24:53to over 8,000 people by the end of the war.
0:25:03 > 0:25:05And this was Welchman's office.
0:25:06 > 0:25:10His vision had turned a country mansion into the world's
0:25:10 > 0:25:12first code-breaking factory.
0:25:14 > 0:25:16Bletchley Park was breaking Enigma daily,
0:25:16 > 0:25:20revealing the inner secrets of the German war machine.
0:25:20 > 0:25:23And it was changing the course of the war.
0:25:26 > 0:25:29They tapped into Rommel's battle plans,
0:25:29 > 0:25:32and his forces were driven out of North Africa.
0:25:37 > 0:25:40They located the U-Boat wolf packs lurking in the Atlantic,
0:25:40 > 0:25:43and these were ruthlessly hunted down.
0:25:44 > 0:25:46And, thanks to Bletchley,
0:25:46 > 0:25:49the allies knew they had successfully deceived Hitler
0:25:49 > 0:25:54into believing the D-Day landings were purely a diversion, leaving his
0:25:54 > 0:25:58forces exposed to the mass invasion of Allied troops that followed.
0:26:02 > 0:26:04The boffins at Bletchley were taking on the might
0:26:04 > 0:26:07of an awe-inspiring Teutonic army and winning.
0:26:10 > 0:26:15Their work has been credited with helping shorten the war by two years
0:26:15 > 0:26:18and Gordon Welchman was central to this achievement.
0:26:19 > 0:26:23To think of him as the Henry Ford of cryptography is not a bad metaphor.
0:26:23 > 0:26:25It's the industrialisation of cryptography.
0:26:25 > 0:26:27That's an astonishing achievement.
0:26:37 > 0:26:41So this is Hut 6. How exciting. This is the place.
0:26:48 > 0:26:50The decoding room.
0:26:52 > 0:26:54Ah, look at these machines.
0:27:05 > 0:27:07So this is administration.
0:27:07 > 0:27:10Ah, this is Dad and Stuart Milner-Barry in this office.
0:27:12 > 0:27:13And I can see who's who.
0:27:13 > 0:27:17There's Dad's pipe. Many memories of him fiddling with pipes.
0:27:17 > 0:27:18There must have been haze of smoke.
0:27:21 > 0:27:23They've done a beautiful job and, look, "Stronger every day,
0:27:23 > 0:27:25"we've got to keep at it."
0:27:25 > 0:27:29They must have needed that a lot during their 15-hour days.
0:27:29 > 0:27:31My goodness, Dad actually sat here.
0:27:35 > 0:27:37When you know how it went
0:27:37 > 0:27:39from just 100 or 200 people
0:27:39 > 0:27:44arriving in August 1939 at Bletchley Park to, you know,
0:27:44 > 0:27:49nearly 10,000 people working there in January 1945...
0:27:49 > 0:27:54If we pick him out as probably the most central figure,
0:27:54 > 0:27:59his legacy is in what Bletchley Park achieved, what Bletchley Park
0:27:59 > 0:28:06contributed to the success and the Allied victory in 1945.
0:28:07 > 0:28:10It's hard to have a bigger legacy than that.
0:28:15 > 0:28:19One war was over, but another was about to start.
0:28:19 > 0:28:21It was to see another remarkable
0:28:21 > 0:28:26contribution from Gordon Welchman, but at a devastating personal cost.
0:28:27 > 0:28:31Operations at Bletchley were finally shut down in the spring of 1946.
0:28:31 > 0:28:34And most of the people who had worked there were allowed to leave
0:28:34 > 0:28:38and rejoin everyday life in post-war Britain.
0:28:38 > 0:28:39But they were given dire warnings
0:28:39 > 0:28:43never to speak of their wartime work.
0:28:43 > 0:28:47The amazing thing about Bletchley, to most of us who survived it,
0:28:47 > 0:28:50was the fact that we did manage to keep it secret.
0:28:50 > 0:28:53I'd never been allowed to talk to anybody
0:28:53 > 0:28:56about what I'd been doing at Bletchley.
0:28:56 > 0:29:00My mother and father didn't know. My wife didn't know when I married her.
0:29:00 > 0:29:07I mean, unbelievable really, that such secrecy should have prevailed.
0:29:07 > 0:29:13Knowing that you've done so much to help change the course of events,
0:29:13 > 0:29:16how do you adjust to a life afterwards?
0:29:19 > 0:29:22However, the legacy of Hut 6 would endure.
0:29:22 > 0:29:26Welchman's creation would find itself the model for GCHQ
0:29:26 > 0:29:31in Britain and the National Security Agency, the NSA, in America.
0:29:31 > 0:29:35But the British Government, almost bankrupt from the war,
0:29:35 > 0:29:38was forced to scale back their operations.
0:29:39 > 0:29:45He found himself more and more frustrated with the attitude
0:29:45 > 0:29:49of the British government towards this new field
0:29:49 > 0:29:53that they'd help create, which is of course this kind of study
0:29:53 > 0:29:57and development of communication systems and of electronics.
0:29:57 > 0:30:00It was such a terrible waste to him.
0:30:01 > 0:30:05Bletchley had led the world with its remarkable inventions,
0:30:05 > 0:30:08but Welchman now thought Britain was squandering this legacy.
0:30:10 > 0:30:14You also have a sense of a man who understands very, very well about the
0:30:14 > 0:30:18computer revolution, the computer age about to come into being, because
0:30:18 > 0:30:22this is a computer age that is brought into being at Bletchley Park.
0:30:23 > 0:30:26Welchman realised he had to seize the opportunity
0:30:26 > 0:30:30to build on what he'd already created at Bletchley Park.
0:30:34 > 0:30:37He was determined to stay at the forefront
0:30:37 > 0:30:38of the computer revolution.
0:30:38 > 0:30:41That meant America.
0:30:43 > 0:30:46NEWSREEL: The Massachusetts Institute of Technology was asked
0:30:46 > 0:30:51by the three military services to establish a new research centre.
0:30:51 > 0:30:57They created MITRE to develop top-secret defence technologies.
0:30:57 > 0:31:00And they were recruiting the finest brains.
0:31:00 > 0:31:04I imagine that the powers that be in England
0:31:04 > 0:31:08got in touch with the powers that be in the United States
0:31:08 > 0:31:12and said they had this wonderful guy and he would like a job.
0:31:14 > 0:31:16Working here put Gordon Welchman
0:31:16 > 0:31:20right back at the heart of another intelligence war. The Cold War.
0:31:33 > 0:31:37NEWSREEL: One of the most dangerous threats to our nation's security
0:31:37 > 0:31:40is the possibility of attack by high-speed enemy bombers
0:31:40 > 0:31:41armed with nuclear weapons.
0:31:43 > 0:31:45This was warfare on a global scale.
0:31:49 > 0:31:52Huge strides in technology were needed
0:31:52 > 0:31:56to hold the so-called Red Menace at bay.
0:31:56 > 0:31:58During that period was the Cuban missile crisis - OK,
0:31:58 > 0:32:02I mean, that was really a tough period, OK?
0:32:02 > 0:32:05I built a bomb shelter in my basement in Bedford, Massachusetts.
0:32:07 > 0:32:11A large-scale nuclear attack on the United States could produce
0:32:11 > 0:32:15a patchwork pattern of fallout covering two-thirds of the nation.
0:32:20 > 0:32:22We cannot afford to take that chance.
0:32:26 > 0:32:29Welchman was given the highest civilian security clearance,
0:32:29 > 0:32:32but it meant becoming a US citizen.
0:32:34 > 0:32:38The job did require a very high security clearance.
0:32:38 > 0:32:40In fact it was high enough
0:32:40 > 0:32:42so that the fact that I had it was classified.
0:32:45 > 0:32:48With the frightening prospect of a nuclear confrontation,
0:32:48 > 0:32:50Welchman was given the vital task of
0:32:50 > 0:32:55ensuring US military communications were capable of withstanding attack.
0:32:58 > 0:33:02All he had learned at Bletchley Park was now applied to help
0:33:02 > 0:33:06achieve American supremacy, on a scale that would dwarf Hut 6.
0:33:08 > 0:33:12Traffic analysis in World War II
0:33:12 > 0:33:16led Welchman to understand the way
0:33:16 > 0:33:21information flowed in battle and how many different ways it flowed.
0:33:23 > 0:33:26Welchman realised military communications
0:33:26 > 0:33:29hadn't really moved on since his days at Bletchley.
0:33:29 > 0:33:33Headquarters issued an order, units made reports.
0:33:35 > 0:33:36But in modern warfare,
0:33:36 > 0:33:40instant access to battlefield information was essential.
0:33:40 > 0:33:43Repeat, this is a yellow alert.
0:33:43 > 0:33:46And computer technology was advancing fast enough
0:33:46 > 0:33:48to make this possible.
0:33:50 > 0:33:52He said, "Hey, with this digital communications,
0:33:52 > 0:33:56"we can do some things that we've never been able to do before".
0:33:56 > 0:34:00Where once he had used traffic analysis to break into German
0:34:00 > 0:34:06networks, now Welchman used all his experience to do the opposite.
0:34:06 > 0:34:10He developed a new kind of network - constantly updated,
0:34:10 > 0:34:13immediately shared and totally secure,
0:34:13 > 0:34:17to serve a battlefield where information was power.
0:34:17 > 0:34:20Everybody periodically broadcast bits of information
0:34:20 > 0:34:22about where they were, what they were doing.
0:34:23 > 0:34:26Welchman called his idea a horseshoe,
0:34:26 > 0:34:30but we would all recognise it today as the cloud.
0:34:34 > 0:34:38Welchman's system instantly connected planes, submarines,
0:34:38 > 0:34:40ground forces, battleships -
0:34:40 > 0:34:44all the elements of the command structure all at the same time.
0:34:48 > 0:34:49And that went out into the sky
0:34:49 > 0:34:53and anybody who was interested in knowing what friendly aircraft
0:34:53 > 0:34:57are in this area could immediately get those reports - sort of
0:34:57 > 0:35:02like an instant Google and this was three, four decades before Google.
0:35:03 > 0:35:07Gordon came up with this radical idea and people looked at it
0:35:07 > 0:35:10and said, "Hey, that's pretty good."
0:35:10 > 0:35:16And so, you know, my boss called me in and said, "OK, make it work".
0:35:18 > 0:35:23His ideas were really a game changer.
0:35:23 > 0:35:26They changed the way people thought about command and control
0:35:26 > 0:35:31and they changed the way battles were managed and warfare was fought.
0:35:31 > 0:35:35It's still in use today and it will be for a long time.
0:35:38 > 0:35:40The legacy of the two giants of Bletchley Park
0:35:40 > 0:35:42endures to the present day.
0:35:42 > 0:35:45Alan Turing made a decisive contribution
0:35:45 > 0:35:47to the computer revolution.
0:35:47 > 0:35:49Gordon Welchman's work prefigured
0:35:49 > 0:35:51how the internet and the cloud would later develop,
0:35:51 > 0:35:55and how technology would enable a surveillance society.
0:36:04 > 0:36:09In 1971, Gordon Welchman moved to the New England town of Newburyport
0:36:09 > 0:36:11and married his third wife, Teeny.
0:36:15 > 0:36:18We started coming pretty much as soon as he moved in,
0:36:18 > 0:36:20and we visited regularly.
0:36:20 > 0:36:23It was a place he really enjoyed.
0:36:23 > 0:36:26He liked living here. He loved the town.
0:36:29 > 0:36:33He was now 65 and still at the peak of his powers.
0:36:33 > 0:36:36He had made a decisive impact on both the Second World War
0:36:36 > 0:36:37and now the Cold War.
0:36:40 > 0:36:41Yet everything he had achieved
0:36:41 > 0:36:44was known only within his clandestine world.
0:36:46 > 0:36:49Remarkably, the success of Bletchley Park
0:36:49 > 0:36:52had stayed secret for two decades.
0:36:53 > 0:36:58But then, in 1974, an event occurred which had unexpectedly
0:36:58 > 0:37:00far-reaching consequences.
0:37:02 > 0:37:06The Ultra Secret, a book by an ex-MI6 Officer,
0:37:06 > 0:37:09revealed for the first time the role of codebreaking
0:37:09 > 0:37:11in winning the Second World War.
0:37:13 > 0:37:16Whitehall agreed that it would be better
0:37:16 > 0:37:19for there to be a controlled disclosure,
0:37:19 > 0:37:22a non-sensational version, by Fred Winterbotham.
0:37:22 > 0:37:24But that opened the floodgates.
0:37:26 > 0:37:30Suddenly daylight was being shone on a hitherto secret world.
0:37:31 > 0:37:35It was a shocking moment for all those, like Welchman,
0:37:35 > 0:37:38who had taken their oath of secrecy so seriously.
0:37:39 > 0:37:44For years and years I didn't even read the histories of the war
0:37:44 > 0:37:48because I was afraid that somehow or other I might reveal
0:37:48 > 0:37:50some things I'd learnt from Ultra.
0:37:52 > 0:37:55Nevertheless, Welchman now felt, for the first time,
0:37:55 > 0:37:58he could tell his family what he had done in the war.
0:38:01 > 0:38:03I think it was an enormous relief.
0:38:03 > 0:38:06He could tell these stories, and could talk to us,
0:38:06 > 0:38:10and could share memories that he'd kept tamped down for so long.
0:38:10 > 0:38:13There was a transformation in his manner.
0:38:13 > 0:38:16I think another thing that was a revelation was the discovery
0:38:16 > 0:38:18that my grandfather, of all people,
0:38:18 > 0:38:21was a sort of prototype of a computer geek.
0:38:23 > 0:38:26By chance, another veteran of the secret war
0:38:26 > 0:38:28was also living in Newburyport.
0:38:28 > 0:38:34I was invited to a dinner party one night. Right there.
0:38:34 > 0:38:40And then, out of a blue sky, Gordon said,
0:38:40 > 0:38:46"Well, I was at Bletchley during the War."
0:38:46 > 0:38:50And, of course, my mouth just fell open,
0:38:50 > 0:38:57because I had been working as an intercept operator at Chicksands.
0:38:57 > 0:39:01All the stuff that we had taken went to Bletchley.
0:39:03 > 0:39:08An idea began to form in Welchman's mind that he should write his story.
0:39:09 > 0:39:12I seem to have a very special responsibility,
0:39:12 > 0:39:16in that I was the only person alive with inside knowledge
0:39:16 > 0:39:19of a very telling episode in cryptologic history.
0:39:23 > 0:39:28In 1977, he also took the deliberate decision to appear on the BBC,
0:39:28 > 0:39:31which, for the first time on television,
0:39:31 > 0:39:35dared to reveal the still-classified story of Ultra intelligence.
0:39:37 > 0:39:40I don't know whether I should say this.
0:39:40 > 0:39:41But it seems to me that...
0:39:43 > 0:39:47..some of the things really have been kept secret too long.
0:39:47 > 0:39:50That there is a point at which...
0:39:52 > 0:39:56..you do more damage by deceiving your own people
0:39:56 > 0:39:59about the true history of World War II than you could possibly do
0:39:59 > 0:40:03by telling now the story as it actually happened.
0:40:11 > 0:40:12He wrote his book here.
0:40:14 > 0:40:16He would go off on his own if he wanted to work,
0:40:16 > 0:40:20and you didn't disturb him, yes, in his study or his office.
0:40:20 > 0:40:24But then he'd emerge, and he'd be Grandad again.
0:40:27 > 0:40:30Determined to set the record straight,
0:40:30 > 0:40:33as well as to give public recognition to those whose work
0:40:33 > 0:40:37had been war-winning, he discreetly contacted old colleagues.
0:40:39 > 0:40:41He wrote from his own prodigious memory.
0:40:41 > 0:40:45He had no access to official papers, which were still classified.
0:40:46 > 0:40:49It would take him seven years.
0:40:49 > 0:40:53I think it was almost a compulsion to write the book.
0:40:53 > 0:40:55It's a very kind of human and understandable thing
0:40:55 > 0:40:59for this man to think, "I don't care how much trouble this gets me into,
0:40:59 > 0:41:02"I want the world to know what I achieved".
0:41:02 > 0:41:07I think my father felt that he had a very important insight
0:41:07 > 0:41:11on a particular piece of history which very few other people had,
0:41:11 > 0:41:14and he just kept reading the obituaries
0:41:14 > 0:41:17and realising that there were fewer and fewer people left.
0:41:18 > 0:41:23The Hut Six Story was published in the United States in February 1982
0:41:23 > 0:41:25and in the UK the following May.
0:41:27 > 0:41:28For the first time in print,
0:41:28 > 0:41:32the full secret history of codebreaking's role in World War II
0:41:32 > 0:41:36was laid bare, including Welchman's use of traffic analysis.
0:41:38 > 0:41:42As well as telling the true history from an insider's perspective,
0:41:42 > 0:41:44the book included a warning.
0:41:45 > 0:41:49Welchman believed lessons from the war were being ignored.
0:41:49 > 0:41:52The Americans were making the very same mistakes
0:41:52 > 0:41:56with their security that the Germans had once made.
0:41:56 > 0:41:58He thought he could talk about this in a way
0:41:58 > 0:42:02that would reach the general public, that would not disclose any secrets,
0:42:02 > 0:42:04it would not tell tales you shouldn't.
0:42:04 > 0:42:06He hoped it would make some money,
0:42:06 > 0:42:08but he really hoped it would generate a conversation.
0:42:10 > 0:42:14The secret world didn't wait long to hit back.
0:42:17 > 0:42:21I was on my way to work and this car speeded up
0:42:21 > 0:42:26and stopped right smack in the, almost in the middle of the road.
0:42:26 > 0:42:29Nobody stops there so I had to see what was going on.
0:42:31 > 0:42:36There's Gordon's house, right there, and then two men jumped out,
0:42:36 > 0:42:42wearing black suit, black tie and black sunglasses.
0:42:42 > 0:42:46They looked like the Men In Black. And they raced across the street.
0:42:46 > 0:42:53Gordon answered the door and you could see them, you know,
0:42:53 > 0:42:58busily discussing something and, all of a sudden, Gordon took the door
0:42:58 > 0:43:02and he slammed it, almost in their faces.
0:43:02 > 0:43:06Later, I found out that it was the National Security Agency.
0:43:06 > 0:43:09There had been books about "the Ultra secret"
0:43:09 > 0:43:12prior to his publication.
0:43:12 > 0:43:15There was no putting the toothpaste back in the tube.
0:43:15 > 0:43:18The secret was out, but Welchman's book was
0:43:18 > 0:43:23the first about cryptanalysis by an actual insider who had done it.
0:43:23 > 0:43:27What Gordon Welchman was doing was not so much disclosing
0:43:27 > 0:43:30the nuts and bolts of attacking Enigma.
0:43:30 > 0:43:35He was saying there is no communication system
0:43:35 > 0:43:40that can resist this kind of cryptanalytical attack.
0:43:40 > 0:43:43NEWSREEL: If our continent were attacked,
0:43:43 > 0:43:48this red telephone would be lifted from its cradle and instantly
0:43:48 > 0:43:52the United States would launch the greatest counterattack in history.
0:43:54 > 0:43:58Signals intelligence remained, at that time,
0:43:58 > 0:44:01at the very heart of the intelligence conflict
0:44:01 > 0:44:04that was being conducted during the Cold War.
0:44:04 > 0:44:08So this was as important and as secret as it could get.
0:44:09 > 0:44:15I think that people who saw what he wrote
0:44:15 > 0:44:17felt he was imperilling current operations.
0:44:19 > 0:44:23Welchman's World War II work in traffic analysis might have
0:44:23 > 0:44:27been 40 years before, but what he had discovered was still so vital to
0:44:27 > 0:44:32the secret world, that revealing it, even now, was considered dangerous.
0:44:35 > 0:44:38It was an irony that would all but destroy him.
0:44:41 > 0:44:46On the 22nd February 1982, the NSA returned.
0:44:46 > 0:44:50These two young gentlemen came in,
0:44:50 > 0:44:51one from NSA and one from,
0:44:51 > 0:44:54I believe it was Air Force intelligence.
0:44:54 > 0:44:59And they said, "This information has never been declassified,
0:44:59 > 0:45:05"and therefore is still in violation of the wartime secrets laws."
0:45:05 > 0:45:08Gordon was taken aback. He said, "This is absurd."
0:45:10 > 0:45:14They were delivering a message to him, and it was an ominous message.
0:45:20 > 0:45:23I believe they had conversations with Mr Welchman.
0:45:23 > 0:45:28Beyond that, I'm not sure that I can talk about anything meaningful.
0:45:29 > 0:45:31It became clear the American authorities
0:45:31 > 0:45:34were not going to back off.
0:45:34 > 0:45:36It was really quite devastating.
0:45:36 > 0:45:39He was quite unprepared for that.
0:45:40 > 0:45:44Welchman knew about another writer who was preparing a book
0:45:44 > 0:45:47revealing the dark secrets of the NSA itself,
0:45:47 > 0:45:51which was doing everything it could to stop publication.
0:45:51 > 0:45:52Welchman enlisted his help.
0:45:52 > 0:45:54We lived in the same area,
0:45:54 > 0:45:57so we could actually get together physically
0:45:57 > 0:45:59and it was the kind of things that you don't want to
0:45:59 > 0:46:03talk over the telephone, especially when you're dealing with NSA.
0:46:03 > 0:46:06They were basically telling him he couldn't write anything.
0:46:06 > 0:46:08He couldn't do any publicity,
0:46:08 > 0:46:12he couldn't answer questions from reporters, he couldn't appear
0:46:12 > 0:46:16on television shows and so forth and that was a really big problem.
0:46:17 > 0:46:21The NSA was effectively trying to kill Welchman's book.
0:46:21 > 0:46:25Threatened with jail, he was forced to cancel all publicity.
0:46:27 > 0:46:30Publication in the UK made matters worse.
0:46:30 > 0:46:33Then-Prime-Minister Margaret Thatcher had to be briefed
0:46:33 > 0:46:36on the problem of Gordon Welchman.
0:46:36 > 0:46:39The Cabinet Secretary wrote to the Prime Minister explaining
0:46:39 > 0:46:43what issues were at stake, also explaining that it was unlikely
0:46:43 > 0:46:47that there was any legal way of proceeding against Gordon Welchman.
0:46:49 > 0:46:52Instead, Bamford believes the British pushed the NSA
0:46:52 > 0:46:54to keep up the pressure on Welchman.
0:46:55 > 0:46:59I think GCHQ played an enormously important role,
0:46:59 > 0:47:03maybe the most important role. I think a lot of the guidance
0:47:03 > 0:47:08that NSA was getting was coming from GCHQ.
0:47:08 > 0:47:10The directors of NSA and GCHQ
0:47:10 > 0:47:14were almost like partners in the same organisation.
0:47:15 > 0:47:18The NSA threatened Welchman with a little-known law
0:47:18 > 0:47:22drafted in 1940 to deal with the sharing of cryptology.
0:47:23 > 0:47:28This same law is now being used on NSA whistle-blower Edward Snowden.
0:47:28 > 0:47:30It's part of the Espionage Act.
0:47:30 > 0:47:33I think it's ten years in prison and a heavy fine.
0:47:34 > 0:47:37So these were very, very serious charges.
0:47:38 > 0:47:40I could see he was nervous.
0:47:40 > 0:47:44I could see the psychical effects that the NSA was having on him.
0:47:45 > 0:47:51That devastates somebody that's spent their entire life trying to protect
0:47:51 > 0:47:55US and British governments and now they're being told that they're going
0:47:55 > 0:48:01to be charged with a crime possibly, of giving secrets to the enemy.
0:48:02 > 0:48:06There was one final act with devastating consequences.
0:48:06 > 0:48:12On the 29th April 1982, Welchman's security clearance was withdrawn.
0:48:13 > 0:48:16All of a sudden, he disappeared.
0:48:16 > 0:48:19"Dear Mr Welchman.
0:48:19 > 0:48:21"As you know, the Department of Defense has raised questions
0:48:21 > 0:48:23"about your recent publication.
0:48:23 > 0:48:28"The MITRE Corporation believes it would be mutually beneficial
0:48:28 > 0:48:32"to temporarily suspend your access to classified materials
0:48:32 > 0:48:34"and technical data in the custody of MITRE,
0:48:34 > 0:48:37"until the situation has been resolved.
0:48:37 > 0:48:40"This suspension is effective this date.
0:48:40 > 0:48:43"Please acknowledge receipt of this letter
0:48:43 > 0:48:45"by signing in the space provided below."
0:48:46 > 0:48:48And he signed below.
0:48:52 > 0:48:57Yes, this would have been... absolutely devastating.
0:48:59 > 0:49:03Rather than stay silent, Welchman went on the offensive.
0:49:04 > 0:49:08He wrote letters and articles which he hoped would exonerate him,
0:49:08 > 0:49:11including a recently discovered unpublished paper,
0:49:11 > 0:49:15"Ultra Revisited: A Tale Of Two Contributors".
0:49:18 > 0:49:22The stories of Alan Turing's life and mine have two things in common.
0:49:24 > 0:49:29First, we were regarded by our boss as the two greatest contributors
0:49:29 > 0:49:32to the wartime success of Bletchley Park.
0:49:32 > 0:49:37Second, we have been branded as "security risks".
0:49:37 > 0:49:39What has happened to me
0:49:39 > 0:49:41can be compared with what happened to Turing.
0:49:44 > 0:49:47For many in the intelligence community, Welchman was being naive
0:49:47 > 0:49:51to imagine he could reveal the secrets of Hut 6 with impunity.
0:49:53 > 0:49:56But he never lost his belief that this was information
0:49:56 > 0:49:58the public needed to know.
0:50:02 > 0:50:05I'm afraid there's a basic fact is that Gordon Welchman
0:50:05 > 0:50:08who had not been involved in any of this after the war,
0:50:08 > 0:50:10was in no position to know himself,
0:50:10 > 0:50:13and was in no position of course to set himself up as the authority
0:50:13 > 0:50:16on what could and could not be released.
0:50:16 > 0:50:21What they didn't stop and think was that the way in which
0:50:21 > 0:50:27cryptanalysts approached the breaking of Enigma was as sensitive
0:50:27 > 0:50:32in the 1980s and is as sensitive today as it was at the time.
0:50:32 > 0:50:35He was getting into an area of decision-making
0:50:35 > 0:50:38that wasn't quite for him.
0:50:39 > 0:50:44With Welchman gagged by the security services, his book flopped.
0:50:44 > 0:50:48The remaining unsold copies of The Hut Six Story were pulped.
0:50:48 > 0:50:52The strain was also coming at a very difficult time.
0:50:52 > 0:50:56He'd had some more medical problems.
0:50:56 > 0:50:59And to add to the pressure, Welchman's wife, Teeny,
0:50:59 > 0:51:02believed they were being put under surveillance.
0:51:03 > 0:51:07She did talk about, you know, the feeling of being watched.
0:51:09 > 0:51:14It really did put a blight on the end of his life.
0:51:14 > 0:51:20It was a cruel irony that Welchman, a master of the secret world,
0:51:20 > 0:51:23who helped win World War II by breaking enemy codes
0:51:23 > 0:51:25and helped the West win the Cold War
0:51:25 > 0:51:27by keeping their communications secret,
0:51:27 > 0:51:31would himself fall foul of the secret state.
0:51:31 > 0:51:37I believe that the rules at the time about secrecy
0:51:37 > 0:51:38were really inflexible.
0:51:38 > 0:51:42The people who administered inflexible rules themselves
0:51:42 > 0:51:45had spent a full career being indoctrinated
0:51:45 > 0:51:49with the idea that secrecy was the base.
0:51:49 > 0:51:53I am, today, glad that the book is out.
0:51:53 > 0:51:56My hunch is it had more to do with the sort of pathological
0:51:56 > 0:52:00and almost hysterical secrecy, which is a kind of British disease
0:52:00 > 0:52:04and it may be that he was just a victim of that in its dying moments.
0:52:05 > 0:52:07I'm not saying that he was blameless.
0:52:07 > 0:52:13He had broken the procedures and the law was never invoked.
0:52:14 > 0:52:17But he lost his job and his livelihood...
0:52:17 > 0:52:22without ever appearing in court or ever facing any criminal charge.
0:52:26 > 0:52:30By now, Welchman was seriously ill with cancer,
0:52:30 > 0:52:33but he continued with his fight to set the record straight.
0:52:33 > 0:52:37It prompted this letter from the head of GCHQ.
0:52:39 > 0:52:43"It was, as I believe you know, a great shock to my predecessor
0:52:43 > 0:52:47"and to the US authorities when you published your book in 1982,
0:52:47 > 0:52:51"without consulting us and in defiance of undertakings
0:52:51 > 0:52:54"which thousands of others have faithfully observed.
0:52:54 > 0:52:58"I am disappointed to find you following a similar path
0:52:58 > 0:53:00"again in 1985."
0:53:00 > 0:53:04The letter went on, "It is a bitter blow to us,
0:53:04 > 0:53:07"as well as a disastrous example to others,
0:53:07 > 0:53:11"when valued ex-colleagues decide to let us down."
0:53:11 > 0:53:13And, finally, you know, I think
0:53:13 > 0:53:17he realised that it wasn't going to go away.
0:53:17 > 0:53:20They probably couldn't successfully prosecute him,
0:53:20 > 0:53:22but they would break him financially.
0:53:24 > 0:53:27Gordon Welchman never redeemed himself.
0:53:27 > 0:53:31Three months later, on October 8th 1985, he died.
0:53:36 > 0:53:40It made two of the last three years of his life really quite hellish.
0:53:42 > 0:53:44But his legacy would continue.
0:53:45 > 0:53:47After his death, his methods
0:53:47 > 0:53:51and insights not only became part of the West's military thinking,
0:53:51 > 0:53:54they became the very heart of the new intelligence networks,
0:53:54 > 0:53:58as the world became more and more connected, via computer.
0:53:59 > 0:54:02In June 2013, Edward Snowden leaked tens of thousands
0:54:02 > 0:54:04of highly classified files.
0:54:06 > 0:54:09Our intelligence agencies were harvesting metadata -
0:54:09 > 0:54:14our phone numbers, our computers' IP addresses,
0:54:14 > 0:54:17the websites we visit, those we message or call
0:54:17 > 0:54:20and where we are at any given moment.
0:54:20 > 0:54:24It suddenly occurred to me that actually what we now do with metadata
0:54:24 > 0:54:26is in a sense a highly-developed version
0:54:26 > 0:54:30of what Welchman started with traffic analysis.
0:54:30 > 0:54:34That's what it is. Metadata and analytics now, in a digital world,
0:54:34 > 0:54:37are essentially our way of doing traffic analysis
0:54:37 > 0:54:39and it can be very, very revealing.
0:54:42 > 0:54:44For many, what Snowden was revealing
0:54:44 > 0:54:47was that we live in a surveillance state,
0:54:47 > 0:54:50that GCHQ and the NSA have turned Welchman's legacy
0:54:50 > 0:54:54against their own citizens, destroying our privacy.
0:54:55 > 0:54:58But, for others, traffic analysis is keeping us safe.
0:55:01 > 0:55:04After 9/11, it was CIA analysts,
0:55:04 > 0:55:07heirs in many ways to Welchman and Bletchley Park,
0:55:07 > 0:55:11who led the hunt for the most wanted man on the planet, Osama Bin Laden.
0:55:14 > 0:55:18If I want to understand how to destroy this terrorist
0:55:18 > 0:55:20organisation, if I want to take them down as an organisation,
0:55:20 > 0:55:23then I have to look for their vulnerabilities, and to look
0:55:23 > 0:55:26for their vulnerabilities, I have to understand their network.
0:55:27 > 0:55:31The technique they used had been pioneered by Gordon Welchman
0:55:31 > 0:55:35in Hut 6. It was the modern equivalent of his traffic analysis.
0:55:37 > 0:55:40What we call link analysis or network analysis - the more
0:55:40 > 0:55:44sophisticated version of that - is the absolutely critical tool
0:55:44 > 0:55:50in finding covert networks, whether it's terrorists or crime networks,
0:55:50 > 0:55:53because they're trying to hide their entire organizational structure.
0:55:53 > 0:55:58How can I find these people or this place? How can I do it
0:55:58 > 0:56:01with enough precision that I'm not just going to bomb an entire town?
0:56:03 > 0:56:07First developed at Bletchley Park and then honed in the States,
0:56:07 > 0:56:13data analysis would now lead a team of US Navy Seals to Osama Bin Laden.
0:56:13 > 0:56:16Today, Edward Snowden is branded a traitor
0:56:16 > 0:56:19for revealing the secrets of modern traffic analysis.
0:56:21 > 0:56:24Gordon Welchman also went public for something he truly believed in.
0:56:24 > 0:56:26But after a glittering career,
0:56:26 > 0:56:30he spent the last three years of his life fighting illness,
0:56:30 > 0:56:32fighting for his reputation
0:56:32 > 0:56:35and feeling outcast from the very world he had helped build.
0:56:42 > 0:56:46Alan Turing's brilliant work at Bletchley Park has made him
0:56:46 > 0:56:48an iconic figure in our history.
0:56:49 > 0:56:53His pioneering spirit sparked the computer revolution
0:56:53 > 0:56:55and is now part of all our lives.
0:56:57 > 0:57:00It was Gordon Welchman's misfortune that his equally brilliantly
0:57:00 > 0:57:04achievement has not earned him the public accolades it deserves.
0:57:06 > 0:57:10His top-secret work impacts on every one of us now
0:57:10 > 0:57:13as much as Turing's.
0:57:13 > 0:57:16But it was to be this very secrecy that was to deny him
0:57:16 > 0:57:19his rightful place in our history.
0:57:21 > 0:57:24Gordon Welchman unquestionably was a genius.
0:57:24 > 0:57:27His genius, however, is probably only recognised
0:57:27 > 0:57:28within the intelligence community
0:57:28 > 0:57:31to which he made such an extraordinary contribution.
0:57:33 > 0:57:3699.9% of the people in the world
0:57:36 > 0:57:40have never heard of Gordon Welchman and you say the name Gordon Welchman
0:57:40 > 0:57:41and they just kind of stare back at you,
0:57:41 > 0:57:45and yet he contributed so much.
0:57:45 > 0:57:48Shortening the war by two years? Good heavens.
0:57:48 > 0:57:54Saving thousands of lives and yet nobody knows who he is.
0:57:56 > 0:57:58I have no qualms about saying he was a genius.
0:58:01 > 0:58:02Of course a theme here
0:58:02 > 0:58:06is "Gordon Welchman, forgotten man of Bletchley Park."
0:58:07 > 0:58:10I'm enormously proud of my grandfather.
0:58:10 > 0:58:14Still sometimes distressed about what happened
0:58:14 > 0:58:18after he published his book and how much that meant to him.
0:58:19 > 0:58:21He was certainly proud of what he'd done.
0:58:21 > 0:58:25There's always an element that it was a pity he didn't get recognised
0:58:25 > 0:58:28but it's too bad he couldn't be here today.