0:00:02 > 0:00:06One thousand years of history under one roof.
0:00:06 > 0:00:11The National Archives, a treasure house of secrets.
0:00:11 > 0:00:15The records of extraordinary times and people.
0:00:15 > 0:00:20These files are this nation's story, our shared past.
0:00:20 > 0:00:24Documents housed here were highly classified,
0:00:24 > 0:00:28intended for the eyes of only the privileged few,
0:00:28 > 0:00:32protected from your sight for decades.
0:00:32 > 0:00:33But not now.
0:00:38 > 0:00:43I've been granted special access to files once kept hush-hush.
0:00:44 > 0:00:49I'll unearth amazing tales from our hidden history.
0:00:49 > 0:00:54Forget what you've been told - these documents tell the truth.
0:01:04 > 0:01:09In this programme, National Security and the birth of a legend.
0:01:11 > 0:01:13The secret letter that preceded
0:01:13 > 0:01:17the storming of the Iranian Embassy by the SAS.
0:01:17 > 0:01:19One of the terrorists was hidden amongst them
0:01:19 > 0:01:21with a hand grenade in his hand,
0:01:21 > 0:01:23and three of us shot him at exactly the same time.
0:01:24 > 0:01:27And the moment you put a bullet in the terrorist, what...
0:01:27 > 0:01:29what was your sensation, then?
0:01:29 > 0:01:31Nothing really. Job done.
0:01:31 > 0:01:34Thinking the unthinkable.
0:01:34 > 0:01:38Churchill's plan for war on Russia, with the Germans as allies.
0:01:38 > 0:01:42They don't imagine that the SS are going to be involved,
0:01:42 > 0:01:44at least in the early months,
0:01:44 > 0:01:46but the Werhmacht, definitely.
0:01:46 > 0:01:49And a conspiracy to decapitate the British cabinet -
0:01:49 > 0:01:53how violent revolutionaries plotted to take over.
0:01:53 > 0:01:57This, which, er, looks strangely like a kitchen recipe,
0:01:57 > 0:01:59except it's for a fire ball.
0:02:03 > 0:02:08The first duty of the State is the protection of its citizens.
0:02:08 > 0:02:11REPORTER: Acting on information that came through yesterday evening,
0:02:11 > 0:02:13an elite group of officers from MI5,
0:02:13 > 0:02:16the Metropolitan Police Anti-Terrorist branch
0:02:16 > 0:02:20and West Midlands Police gathered in Birmingham for a pre-dawn raid...
0:02:21 > 0:02:23And today the State is kept very busy
0:02:23 > 0:02:28with threats of attack constantly in the news.
0:02:28 > 0:02:31Detectives have been combing the route of the train to London
0:02:31 > 0:02:32the men took last week.
0:02:32 > 0:02:36This evening, police carried out a controlled explosion
0:02:36 > 0:02:39on a car at Luton station, the area remains sealed off...
0:02:39 > 0:02:44For obviously reasons, national security is cloaked in secrecy.
0:02:44 > 0:02:49Decades can pass before operational details are revealed.
0:02:54 > 0:02:56Here in the National Archives,
0:02:56 > 0:02:59I've discovered an extraordinary dossier
0:02:59 > 0:03:03that sheds new light on an infamous terrorist siege
0:03:03 > 0:03:05that many of us remember.
0:03:06 > 0:03:07It all began when three armed men
0:03:07 > 0:03:10seized the lone police guard outside the Embassy,
0:03:10 > 0:03:12bundled him inside and fired three shots.
0:03:12 > 0:03:15Seconds later Iranian women rushed screaming from the building,
0:03:15 > 0:03:19and seconds after that the first reinforcements arrived.'
0:03:19 > 0:03:24In April, 1980, armed men forced their way into the Iranian Embassy
0:03:24 > 0:03:27in London, taking 26 people hostage.
0:03:28 > 0:03:32They wanted to draw the world's attention to political prisoners
0:03:32 > 0:03:36held by Iran's new revolutionary leader, Ayatollah Khomeini.
0:03:36 > 0:03:39The six gunmen demanded those prisoners' release
0:03:39 > 0:03:43and safe passage out of the United Kingdom for themselves.
0:03:46 > 0:03:48As millions watched the siege on TV,
0:03:48 > 0:03:52another drama was unfolding behind the scenes.
0:03:52 > 0:03:56The Iranians made contact with the Thatcher Government in London.
0:03:58 > 0:04:01To see something on television is only half the story.
0:04:01 > 0:04:05You find out the rest when you open the files.
0:04:05 > 0:04:10For a start, the Iranian Embassy was considered Iranian territory
0:04:10 > 0:04:11and the British Government
0:04:11 > 0:04:14could only legally assault it with an invitation.
0:04:14 > 0:04:16Here is the invitation,
0:04:16 > 0:04:19and it was delivered in the most extraordinarily
0:04:19 > 0:04:20flowery diplomatic language.
0:04:20 > 0:04:24"The Embassy of Islamic Republic of Iran presents its compliments
0:04:24 > 0:04:27"to His Excellency, the Foreign Secretary and has the honour to draw
0:04:27 > 0:04:32"draw to his Excellency's attention the incidence at this Embassy
0:04:32 > 0:04:35"today in which lives of 20-odd diplomats and staff,
0:04:35 > 0:04:38"including the Charge D'Affairs and several women,
0:04:38 > 0:04:41"is under constant threat of death.
0:04:41 > 0:04:44"It is requested that His Excellency the Foreign Secretary
0:04:44 > 0:04:47"will appreciate the severity of the threat and will order
0:04:47 > 0:04:50"the security forces to take all possible measures
0:04:50 > 0:04:52"to safeguard lives".
0:04:52 > 0:04:55That letter authorised Britain's Home Secretary
0:04:55 > 0:04:59to do whatever was needed to end the siege.
0:05:00 > 0:05:05In Whitehall, civil servants urgently considered how the siege
0:05:05 > 0:05:09might conclude and the consequences of each possibility.
0:05:09 > 0:05:12Best outcome - terrorists surrender.
0:05:12 > 0:05:16Worst outcome - the emergency shoot out.
0:05:16 > 0:05:17Intermediate outcomes -
0:05:17 > 0:05:20let terrorists go with all hostages,
0:05:20 > 0:05:22let them go with some hostages,
0:05:22 > 0:05:24let them go with no hostages.
0:05:24 > 0:05:26Whoever wrote this memo didn't know Margaret Thatcher.
0:05:26 > 0:05:29For her, any option that began "Let terrorists go"
0:05:29 > 0:05:33would have been considered as a worst option.
0:05:33 > 0:05:35REPORTER: What makes you believe
0:05:35 > 0:05:39- that taking over the Embassy in London...- Yeah.
0:05:39 > 0:05:45..will force the Iranian Government to carry out your demands?
0:05:45 > 0:05:48- TELEPHONE:- Er, you know, it is one of the means
0:05:48 > 0:05:55that we want to send our voice to the world.
0:05:55 > 0:05:59Are you saying that all the hostages are safe tonight?
0:06:01 > 0:06:04- What? - All the hostages are safe tonight?
0:06:04 > 0:06:05Yeah.
0:06:07 > 0:06:12In the first days of the siege, the authorities focused on negotiation,
0:06:12 > 0:06:18making minor concessions such as broadcasting the gunman's demands.
0:06:18 > 0:06:23As a result, five hostages were released,
0:06:23 > 0:06:27but the terrorists became impatient.
0:06:27 > 0:06:30On the sixth day of the siege, everything changed.
0:06:30 > 0:06:33The gunmen inside the Embassy became frustrated
0:06:33 > 0:06:37that their major demands were not being met.
0:06:37 > 0:06:42The put three bullets into one of the hostages and bundled his body
0:06:42 > 0:06:46out of the front door, threatening to kill more hostages.
0:06:46 > 0:06:50The Commissioner of the Metropolitan Police sought the Government's
0:06:50 > 0:06:55permission to hand the situation over to the British Army.
0:06:55 > 0:06:58Something's got to be done because they're killing hostages,
0:06:58 > 0:06:59then you've got to go in,
0:06:59 > 0:07:02you've got to blow the doors, you've got to blow the windows,
0:07:02 > 0:07:04you've got to attack and hope for the best.
0:07:04 > 0:07:08'Robin Horsfall was one of a 40-strong SAS team
0:07:08 > 0:07:10'put on immediate standby.
0:07:10 > 0:07:14'As they readied themselves, their commanding officers
0:07:14 > 0:07:17'gathered intelligence and planned an attack.'
0:07:18 > 0:07:22There are 54 rooms in that building and five floors.
0:07:22 > 0:07:26The idea was to hit every room, every entrance, every entry point
0:07:26 > 0:07:31at exactly the same time to create that speed and surprise and shock.
0:07:31 > 0:07:35'Robin's SAS unit was transported to London in secrecy
0:07:35 > 0:07:39'and housed in the Royal College of General Practitioners,
0:07:39 > 0:07:42'two doors away from the Iranian Embassy.
0:07:42 > 0:07:44'Here they awaited the order to go.'
0:07:44 > 0:07:4740 of us cooped up in there,
0:07:47 > 0:07:50watching the Embassy Snooker Championships on television
0:07:50 > 0:07:53hour after hour, the most exciting thing ever.
0:07:53 > 0:07:57We got a little bit carried away occasionally, playing silly games,
0:07:57 > 0:08:02drilling holes in each other's mugs of tea, and one guy got his
0:08:02 > 0:08:06training shoes nailed to the floor, as soldiers do when they're bored.
0:08:06 > 0:08:09Erm, the police thought we were complete and utter idiots.
0:08:09 > 0:08:13'But, shortly afterwards, the SAS demonstrated their serious side.'
0:08:13 > 0:08:15There they go, there they go.
0:08:15 > 0:08:17EXPLOSION
0:08:21 > 0:08:25At 7:23pm, Operation Nimrod began.
0:08:29 > 0:08:32It put a secret and shadowy organisation
0:08:32 > 0:08:34on prime-time television.
0:08:36 > 0:08:39SCREAMING AND GUNFIRE
0:08:39 > 0:08:41So which level were you coming in at?
0:08:41 > 0:08:44I was on this level, the ground floor level, on the back door.
0:08:46 > 0:08:47The assault started.
0:08:47 > 0:08:50As I'm standing on the back door, the guys are abseiling
0:08:50 > 0:08:52down the back of the building.
0:08:52 > 0:08:57Er, Tom Morrell get his hand and glove caught in his abseil harness
0:08:57 > 0:08:59and he gets stuck above the window.
0:08:59 > 0:09:01The guys beneath him have gone through,
0:09:01 > 0:09:04thrown in the flash-bangs, the windows have caught fire,
0:09:04 > 0:09:07the flames are lapping up underneath him and he's starting to burn alive
0:09:07 > 0:09:10hanging on this rope, so he's kicking himself out
0:09:10 > 0:09:12away from the building,
0:09:12 > 0:09:15and he's about 25 feet up above the concrete floor.
0:09:15 > 0:09:18The guys on the roof, seeing him stuck, are trying to cut the rope
0:09:18 > 0:09:21under tension to drop him down on the balcony.
0:09:21 > 0:09:22But if they cut the rope while
0:09:22 > 0:09:26he's swinging outwards, he's going to go over the balcony and die.
0:09:26 > 0:09:28Er, as I'm standing there looking up at him
0:09:28 > 0:09:31with nothing to do, three rounds came through the window
0:09:31 > 0:09:33and I think, "Oh, the guys are in there doing their job,
0:09:33 > 0:09:35"doosh-doosh-doosh" through the window.
0:09:35 > 0:09:40Erm, Hector is on the radio and he goes, "Reserves go in".
0:09:40 > 0:09:42SCREAMING
0:09:42 > 0:09:45So we go through the door and the hostages are coming down.
0:09:45 > 0:09:48One of the terrorists was hidden amongst them with a hand grenade
0:09:48 > 0:09:51in his hand, and three of us shot him at exactly the same time.
0:09:51 > 0:09:53SOUND OF GUNFIRE
0:09:54 > 0:09:59He had 27 holes in him and he collapsed and died immediately.
0:09:59 > 0:10:02And the moment that you put a bullet in the terrorist, what...
0:10:02 > 0:10:04what was your sensation then?
0:10:04 > 0:10:06Nothing really. Job done.
0:10:06 > 0:10:10It was no more relevant than to have a slice of toast in the morning.
0:10:10 > 0:10:12It was easy.
0:10:12 > 0:10:15People make a great furore about
0:10:15 > 0:10:19the emotional difficulties of killing somebody,
0:10:19 > 0:10:22but if you've been trained to do that since the age of 15
0:10:22 > 0:10:26and to do it properly and do it for the right reasons,
0:10:26 > 0:10:29then it's not a difficult thing to do at all.
0:10:30 > 0:10:34Early in the operation, the gunmen killed another hostage.
0:10:34 > 0:10:38By the time it was over, just 15 minutes later,
0:10:38 > 0:10:41five of the terrorists were dead, the sixth in handcuffs.
0:10:43 > 0:10:5019 hostages were rescued and the SAS emerged as international heroes.
0:10:52 > 0:10:56The reaction of the whole world was amazing.
0:10:56 > 0:10:59It was the biggest news that this nation had had
0:10:59 > 0:11:02since the death of Winston Churchill.
0:11:02 > 0:11:05It was massive and everybody wanted to know us.
0:11:05 > 0:11:09'Amongst the first on the scene to congratulate the soldiers
0:11:09 > 0:11:12'was the Prime Minister, Mrs Thatcher, who watched with them
0:11:12 > 0:11:14'television reports of the operation.
0:11:14 > 0:11:19'Britain's special forces had acquired a fearsome reputation.'
0:11:19 > 0:11:22Do you think the operation made Britain a safer place?
0:11:22 > 0:11:24The operation definitely made Britain
0:11:24 > 0:11:28a safer place for a long time, cos the mythology that grew
0:11:28 > 0:11:33around our special forces protected us for a long period of time.
0:11:33 > 0:11:36It frightened people so, instead of mounting an operation here,
0:11:36 > 0:11:38they went somewhere else to do it.
0:11:40 > 0:11:44With the dramatic assault across these balconies,
0:11:44 > 0:11:47Britain gained an overnight reputation
0:11:47 > 0:11:50for zero-tolerance of terrorism.
0:11:50 > 0:11:51The Iranians, of course,
0:11:51 > 0:11:54were pleased that the siege had been lifted,
0:11:54 > 0:11:56but they also had reason for complaint.
0:11:56 > 0:11:59Just before the siege began, they had written to Britain's
0:11:59 > 0:12:04Diplomatic Protection Group warning that they needed extra security,
0:12:04 > 0:12:09saying in their letter that, "Forces hostile to Iran
0:12:09 > 0:12:12"are planning acts of sabotage."
0:12:14 > 0:12:17After the siege was over, the Iranians complained that,
0:12:17 > 0:12:23though their letter of warning had been received, it had been ignored.
0:12:23 > 0:12:27As these files show, a Whitehall official was told to investigate.
0:12:28 > 0:12:32The civil servant here says, "I spoke to the Chief Superintendant
0:12:32 > 0:12:35"and he categorically denied the story".
0:12:35 > 0:12:38But, a few days later,
0:12:38 > 0:12:41"He's checked his records and confirms that
0:12:41 > 0:12:47"a letter from the Iranians was sent to the Diplomatic Protection Group".
0:12:51 > 0:12:54But that wasn't the end of the correspondence,
0:12:54 > 0:12:57because it's now emerged that, shortly after the British
0:12:57 > 0:13:01received the warning letter from the Iranians, they had written back.
0:13:03 > 0:13:06The Diplomatic Protection Group replied that it kept
0:13:06 > 0:13:11the political climate affecting Iran under constant review,
0:13:11 > 0:13:15and it pledged to accord to the Embassy
0:13:15 > 0:13:17"our urgent attention at all times".
0:13:17 > 0:13:24Unfortunately, this reassuring reply was delivered to the Embassy
0:13:24 > 0:13:26only after the siege was over.
0:13:38 > 0:13:42During World War II, Britain moved from the brink of defeat
0:13:42 > 0:13:44to victory,
0:13:44 > 0:13:48but emerged exhausted after five years of conflict.
0:13:48 > 0:13:52As Hitler neared his defeat, Winston Churchill was planning
0:13:52 > 0:13:56a new confrontation against a new enemy.
0:13:56 > 0:14:00ORCHESTRAL MUSIC PLAYS
0:14:05 > 0:14:10In these fascinating files, we learn that Winston Churchill
0:14:10 > 0:14:14was prepared to contemplate total war against Russia.
0:14:14 > 0:14:19These files labelled, "Russia Threat to Western Civilisation"
0:14:19 > 0:14:22and, of course, marked "Top Secret",
0:14:22 > 0:14:26reveal the idea of opening a war against Russia
0:14:26 > 0:14:29on the 1st of July, 1945.
0:14:29 > 0:14:33"The overall or political object is to impose upon Russia
0:14:33 > 0:14:37"the will of the United States and the British Empire."
0:14:37 > 0:14:42And that is initialled WSC, Winston Spencer Churchill,
0:14:42 > 0:14:4610th of June, 1945.
0:14:46 > 0:14:53The assessment of the military planners is not optimistic.
0:14:53 > 0:14:56"The result of a total war with Russia is not possible to forecast,
0:14:56 > 0:15:00"but the one thing certain is that to win
0:15:00 > 0:15:03"it would take us a very long time."
0:15:03 > 0:15:07For those in Eastern Europe who may believe that the Allies
0:15:07 > 0:15:10reached a pretty feeble peace with the Soviet Union
0:15:10 > 0:15:14at the end of the European War, it may be of interest to know
0:15:14 > 0:15:16that Winston Churchill, at least,
0:15:16 > 0:15:18was prepared to think the unthinkable.
0:15:21 > 0:15:24How could he contemplate another war
0:15:24 > 0:15:28when we were just completing our defeat of the Nazis?
0:15:28 > 0:15:31Because the Russians had imposed communism
0:15:31 > 0:15:34in parts of Eastern Europe, including Poland,
0:15:34 > 0:15:39which was intolerable since Britain had guaranteed Polish independence
0:15:39 > 0:15:42and gone to war for it six years before.
0:15:42 > 0:15:46This is a secret that's lain entombed for quite a long time
0:15:46 > 0:15:50Exactly, and I believe the document that's in the National Archives
0:15:50 > 0:15:54is the only one that is in the public domain.
0:15:54 > 0:15:56Did Churchill mean it seriously?
0:15:56 > 0:15:58I mean, I just wonder was he trying to assuage his conscience,
0:15:58 > 0:16:02and he thought, "I'd better look at this and see whether it's feasible"?
0:16:02 > 0:16:06Or did Churchill really believe that we could spend, I don't know,
0:16:06 > 0:16:08another three or four years fighting Russia?
0:16:08 > 0:16:10Of course, Churchill's passions swing high and low
0:16:10 > 0:16:14during this period - one minute he's thinking he can deal with Stalin,
0:16:14 > 0:16:18the next minute he's totally fed up and angry with Stalin,
0:16:18 > 0:16:20so he does swing emotionally.
0:16:20 > 0:16:24SOLDIER SPEAKS IN RUSSIAN
0:16:28 > 0:16:32Churchill's war plans are a shock
0:16:32 > 0:16:36and so is his idea of the alliance that he might put together.
0:16:40 > 0:16:45One of the things that astonished me about the file, is the thought that
0:16:45 > 0:16:50the German Army could fight alongside the British Army
0:16:50 > 0:16:52against the Russians,
0:16:52 > 0:16:55and when Hitler is scarcely cold in his grave.
0:16:55 > 0:16:57Exactly.
0:16:57 > 0:17:01The Germans are not designed to come into the conflict
0:17:01 > 0:17:04on the 1st of July, the start date of operations.
0:17:04 > 0:17:07It's thought they're going to be introduced some months later,
0:17:07 > 0:17:09after the Allies have equipped them
0:17:09 > 0:17:11properly and how they'd train together.
0:17:11 > 0:17:14They don't imagine that the SS are going to be involved,
0:17:14 > 0:17:16- at least in the early months.- OK.
0:17:16 > 0:17:18But the Wehrmacht, definitely.
0:17:18 > 0:17:21MUSIC: Do I Worry? by The Ink Spots
0:17:21 > 0:17:24When he received the opinion of his military chiefs,
0:17:24 > 0:17:26Churchill faced up to reality.
0:17:26 > 0:17:30Operation Unthinkable was unachievable,
0:17:30 > 0:17:34particularly as it needed the support of the Americans,
0:17:34 > 0:17:36who weren't prepared to give it.
0:17:36 > 0:17:39But his fears about Stalin's aggression
0:17:39 > 0:17:41proved to be well-founded.
0:17:41 > 0:17:43# Do I worry?
0:17:43 > 0:17:46# You can bet your life
0:17:46 > 0:17:49# I do. #
0:17:49 > 0:17:52Do you see it just as another example of his extraordinary
0:17:52 > 0:17:55breadth of vision, that he could THINK about another war?
0:17:56 > 0:18:00I think he was extremely realistic of the problems we had
0:18:00 > 0:18:02with the Soviet Union then,
0:18:02 > 0:18:06and, of course, as the months go on the Americans start to realise
0:18:06 > 0:18:09the sense that Churchill is talking.
0:18:09 > 0:18:12The Americans are waking up to the threat from Stalin,
0:18:12 > 0:18:15and they have their own version of Operation Unthinkable,
0:18:15 > 0:18:18Operation Pincher,
0:18:18 > 0:18:20which is thinkable.
0:18:20 > 0:18:22And what does that result in?
0:18:22 > 0:18:25That results, eventually, in nuclear war.
0:18:25 > 0:18:29# Do I worry?
0:18:29 > 0:18:32# You can bet your life
0:18:32 > 0:18:38# I do. #
0:18:42 > 0:18:45MILITARY MARCHING MUSIC
0:18:51 > 0:18:57The British have a long and proud history of peaceful protest.
0:18:57 > 0:18:59No-one makes a placard better.
0:18:59 > 0:19:03MUSIC CONTINUES
0:19:07 > 0:19:11But some groups want nothing short of revolution.
0:19:11 > 0:19:14CROWDS YELL AND ROAR
0:19:17 > 0:19:22In the early 1800s, Britain was gripped by an age of austerity.
0:19:22 > 0:19:25The Napoleonic Wars had recently ended
0:19:25 > 0:19:29and thousands of unemployed former sailors and soldiers
0:19:29 > 0:19:33came back to civvy street, trying and failing to find work.
0:19:35 > 0:19:37There were demonstrations and riots.
0:19:37 > 0:19:41So serious was the unrest that the Government brought in
0:19:41 > 0:19:45new measures forbidding crowds from gathering in the streets.
0:19:47 > 0:19:49But it was behind closed doors
0:19:49 > 0:19:52that a bloody coup was being planned.
0:19:53 > 0:19:56A document I've unearthed at the National Archives
0:19:56 > 0:20:03reveals the horrifying plot hatched by Anti-Government radicals in 1820
0:20:03 > 0:20:05to assassinate the British cabinet.
0:20:05 > 0:20:08This was the Cato Street Conspiracy.
0:20:10 > 0:20:11What was it all about?
0:20:11 > 0:20:15Well, here are their aims expressed in a coded message.
0:20:15 > 0:20:18It was sent in strips which could then be
0:20:18 > 0:20:20pieced together by the recipients.
0:20:20 > 0:20:25And this is an appeal to the army to "Mutiny, brave soldiers!
0:20:25 > 0:20:27"The tyrants are no more.
0:20:27 > 0:20:31"Make common cause with the people, think of your fathers,
0:20:31 > 0:20:33"mothers and friends.
0:20:33 > 0:20:37"Be just to the miseries that they have long endured.
0:20:37 > 0:20:43"Be just to yourselves, be brave and be free, join the people."
0:20:43 > 0:20:46Strong language indeed.
0:20:46 > 0:20:50But the rebels weren't fighting a war of words.
0:20:50 > 0:20:53They were cooking up something lethal,
0:20:53 > 0:20:58so dangerous that its ingredients will now be bleeped.
0:20:58 > 0:21:03This, which looks strangely like a kitchen recipe,
0:21:03 > 0:21:05except it's for a fire ball.
0:21:05 > 0:21:09- Take 2 oz of- BLEEP,- 2 oz of- BLEEP.
0:21:09 > 0:21:13- Melt together and when beginning to cool, add 2 oz of- BLEEP.
0:21:13 > 0:21:16Make it into a ball with a fuse fixed in
0:21:16 > 0:21:19- from the centre composed of- BLEEP.
0:21:19 > 0:21:21EXPLOSIVE BANG
0:21:21 > 0:21:24And, if bombs weren't terrible enough,
0:21:24 > 0:21:27their plans for the cabinet were grizzly.
0:21:27 > 0:21:31These pike heads, 250 of them.
0:21:32 > 0:21:35They are vicious little implements.
0:21:35 > 0:21:40Very, very sharp, with nasty little teeth and grooves.
0:21:40 > 0:21:44One of them had said that he intended to use his knife
0:21:44 > 0:21:47to cut off the heads of two members of the cabinet,
0:21:47 > 0:21:52Sidmouth and Castlereagh, and then to display their heads on pikes.
0:21:55 > 0:22:00Despite their careful preparations, the rebels were doomed to failure.
0:22:00 > 0:22:05One of their number, George Edwards, was a government spy.
0:22:05 > 0:22:09He'd been feeding details of the plot to the authorities.
0:22:09 > 0:22:14As the conspirators assembled in London's Cato Street, ready to start
0:22:14 > 0:22:19their revolution, they were about to discover that they'd been betrayed.
0:22:22 > 0:22:30Behind this tiny facade, a plot of immeasurable audacity was underway.
0:22:30 > 0:22:32This was a dilapidated tenement,
0:22:32 > 0:22:37a stable below with a loft above, reached by a ladder.
0:22:37 > 0:22:40On the evening of the 23rd February, 1820,
0:22:40 > 0:22:42the building was stormed by a dozen policemen,
0:22:42 > 0:22:44Bow Street Runners,
0:22:44 > 0:22:48who didn't wait for the Cold Stream Guards, who were in reserve.
0:22:48 > 0:22:51During the course of the attack, a policeman was killed.
0:22:51 > 0:22:53A large number of traitors made their escape,
0:22:53 > 0:23:00but a smaller number was apprehended and the conspiracy was thwarted.
0:23:06 > 0:23:08CROWDS BAY AND YELL
0:23:17 > 0:23:22This was the very room where the police found the conspirators.
0:23:22 > 0:23:26A contemporary illustration shows the leader, Arthur Thistlewood,
0:23:26 > 0:23:31fatally stabbing one of the Bow Street Runners, John Smithers.
0:23:31 > 0:23:33There was a scene of pandemonium.
0:23:33 > 0:23:35MOBS YELL AND BAY
0:23:37 > 0:23:43But at the end of it there was a cache of arms and explosives
0:23:43 > 0:23:47providing easily enough evidence to convict the conspirators.
0:23:49 > 0:23:52Their trial revealed something sensational.
0:23:52 > 0:23:56Not only had George Edwards, the Government mole,
0:23:56 > 0:24:01been spying on the rebels, he was an agent provocateur.
0:24:01 > 0:24:04He'd actively encouraged them in their plans
0:24:04 > 0:24:06to murder cabinet members.
0:24:06 > 0:24:10Why would the Government risk promoting a revolution?
0:24:10 > 0:24:13Professor John Gardner has his own theory.
0:24:14 > 0:24:18I think the best way to avoid a revolution is to create one
0:24:18 > 0:24:21and then to publically crush it.
0:24:21 > 0:24:25In May of 1820, the five conspirators
0:24:25 > 0:24:28were executed at Newgate in front of massive crowds,
0:24:28 > 0:24:32it's said that 100,000 people had seen them being executed there.
0:24:32 > 0:24:36And what happened is they were hanged and then decapitated.
0:24:36 > 0:24:40And this had a real deadening effect, because it seemed that
0:24:40 > 0:24:43the Government was so ruthlessly well organised,
0:24:43 > 0:24:46that they could crush a rebellion before it had even happened.
0:24:46 > 0:24:51If the idea was to discourage other treacherous plots, it was effective.
0:24:52 > 0:24:55There were no executions for high treason again
0:24:55 > 0:24:57until the Easter Risings in 1916.
0:24:57 > 0:25:01So it's a real watershed moment. That's the last time that
0:25:01 > 0:25:05anybody's executed for high treason for almost 100 years.
0:25:11 > 0:25:15The Cato Street Plot was undermined
0:25:15 > 0:25:19by a highly effective mole placed inside the conspiracy.
0:25:19 > 0:25:24Ever since then, the authorities have been tempted to infiltrate
0:25:24 > 0:25:28protest groups, fearing their radical agenda -
0:25:28 > 0:25:32sometimes with highly controversial results.
0:25:32 > 0:25:34ROCK MUSIC PLAYS
0:25:51 > 0:25:56I'm meeting Dr Rory Cormac
0:25:56 > 0:26:01at a London hotel once populated by the intelligence services.
0:26:01 > 0:26:03He knows the rules of the spying game.
0:26:05 > 0:26:08Is there much of a difference, really, between infiltrating
0:26:08 > 0:26:11a foreign organisation, an enemy power
0:26:11 > 0:26:14and infiltrating organisations at home of your own citizens?
0:26:14 > 0:26:18The big difference between infiltrating foreign organisations
0:26:18 > 0:26:21and domestic ones, is going to be the idea of ethics,
0:26:21 > 0:26:22the idea of how right it is
0:26:22 > 0:26:26to monitor and put surveillance on your own subjects.
0:26:26 > 0:26:28It muddies the water slightly.
0:26:28 > 0:26:31People are generally OK with the Government
0:26:31 > 0:26:33doing things against people overseas.
0:26:33 > 0:26:37When it's done closer to home, deeper questions get asked.
0:26:38 > 0:26:41I was very struck in the case of the Cato Street Conspiracy,
0:26:41 > 0:26:45it is alleged that the Government spy was actually
0:26:45 > 0:26:47so much at the heart of it that there would not have been
0:26:47 > 0:26:51a conspiracy, at least in that form, if he hadn't been part of it,
0:26:51 > 0:26:53the Government plant.
0:26:53 > 0:26:56Can you think of other instances where that may have been case?
0:26:56 > 0:26:58It's an interesting allegation,
0:26:58 > 0:27:01the idea of using an agent provocateur, I suppose.
0:27:01 > 0:27:05And there are no other incidents I can think of
0:27:05 > 0:27:09which have been proven where governments have deliberately
0:27:09 > 0:27:12instigated some sort of subversion in order to clamp down on it.
0:27:12 > 0:27:15It's the equivalent of the controlled explosion, isn't it?
0:27:15 > 0:27:18If you know that something may go off at a time
0:27:18 > 0:27:21not of your choosing, it's perhaps better to make it go off
0:27:21 > 0:27:22at a time that you have selected?
0:27:22 > 0:27:24Yes, and there's a perfectly logical
0:27:24 > 0:27:26and valid way of looking at it.
0:27:26 > 0:27:29One of the difficulties when we talk about intelligence is
0:27:29 > 0:27:31so much of this stuff's classified,
0:27:31 > 0:27:33and when we're looking at contemporary examples,
0:27:33 > 0:27:37in operations against Al-Qaeda or whomever, we simply don't yet know,
0:27:37 > 0:27:40and I for one, as a historian, am really looking forward
0:27:40 > 0:27:42to finding out the files in 30, 40, 50 years' time.
0:27:42 > 0:27:45I'm looking forward to presenting the programmes
0:27:45 > 0:27:47- in 30 or 40 years' time. - RORY LAUGHS
0:27:50 > 0:27:53In 1820, here in Cato Street,
0:27:53 > 0:27:56and in 1980 in Princes Gate,
0:27:56 > 0:28:02British security forces raided London houses with deadly success.
0:28:02 > 0:28:08Even more audacious was the plan in July, 1945,
0:28:08 > 0:28:12to attack the Soviet Union, a raid to seize back Poland
0:28:12 > 0:28:17not surprisingly codenamed Operation Unthinkable.
0:28:17 > 0:28:22Unthinkable to everyone, perhaps, except Winston Churchill,
0:28:22 > 0:28:26one of the boldest minds in history.