0:00:02 > 0:00:07Nothing in our landscape is here by accident. It's all part of the incredible story
0:00:07 > 0:00:11of how people have shaped our country over thousands of years.
0:00:11 > 0:00:15Every ridge, every bump has a meaning.
0:00:15 > 0:00:23I'm Ben Robinson. As an archaeologist it's my job to unpick the great story we've inherited.
0:00:23 > 0:00:28From my perspective, the best way to do that is up here in the air.
0:00:32 > 0:00:39Aerial photography is challenging our views of some of our most iconic landscapes.
0:00:39 > 0:00:45I'm flying along the Thames to find a part of our military history that was lost in just a few generations.
0:00:45 > 0:00:51Is it possible that experimental research carried out here helped to change the course of WWI?
0:01:07 > 0:01:12The history of the Thames and the history of the defence of Britain are intertwined,
0:01:12 > 0:01:18yet there's one important part of that story that's been largely overlooked. It all took place
0:01:18 > 0:01:22in an area many people have never even heard of.
0:01:22 > 0:01:24We're flying over the Dartford Crossing.
0:01:24 > 0:01:29We've got Essex on my left, Kent on my right, but we're heading
0:01:29 > 0:01:32to the Hoo Peninsula. Down this way.
0:01:32 > 0:01:39The Hoo sits on the Kent coast, flanked by the Thames to its north and the River Medway to its south.
0:01:39 > 0:01:45Over the past 150 years, this place has played a major role in British military history.
0:01:45 > 0:01:51It seems incredible, yet many stories of the breakthroughs that happened here have been forgotten.
0:01:51 > 0:01:58Until now we've been missing a key chapter in the history of the First World War.
0:01:58 > 0:02:02For while decisions of state were made miles upstream at Westminster,
0:02:02 > 0:02:06it was here in what Dickens called "the wild, flat marshes"
0:02:06 > 0:02:12that the dirty, gritty, industrial nature of modern warfare was being forged.
0:02:12 > 0:02:18Much of the work done here was top secret. Very few records were kept.
0:02:18 > 0:02:24Archaeologists at English Heritage have been carrying out the first survey of the whole peninsula,
0:02:24 > 0:02:28recording every lump of concrete, every mound, from the air.
0:02:28 > 0:02:34So now we can begin to piece together the untold story of exactly what went on here on the Hoo.
0:02:36 > 0:02:42And I want to uncover those secrets, find out how people lived, worked, sometimes died here,
0:02:42 > 0:02:44right here on the home front.
0:02:44 > 0:02:49It doesn't take long to see this area has a rich military past.
0:02:49 > 0:02:54The lower reaches of the Thames are punctuated by a defensive ring of coastal forts
0:02:54 > 0:03:00going back centuries. They were built to repel any attacker heading up river to the capital.
0:03:00 > 0:03:03Some were still in use during WWI.
0:03:03 > 0:03:09Today many are abandoned and decaying so it's a race against time to research and record them.
0:03:10 > 0:03:14The best way to see them in context is from the air.
0:03:14 > 0:03:18From here you can see how the whole network of forts fits together.
0:03:18 > 0:03:21They're really quite close.
0:03:21 > 0:03:26It's difficult to imagine how a ship could get between them without being hit.
0:03:26 > 0:03:32From the aerial survey, it was immediately clear that Cliffe Fort on the Thames shoreline of the Hoo
0:03:32 > 0:03:37is at particular risk. It also has some unusual features.
0:03:37 > 0:03:41Archaeologists are now investigating it fully for the first time.
0:03:41 > 0:03:46'Peter Kendall from English Heritage is one of those carrying out the work.'
0:03:46 > 0:03:52It was built in the middle of the 19th century after a Royal Commission called by Lord Palmerston.
0:03:52 > 0:03:57There was a genuine belief that the French would possibly invade us.
0:03:57 > 0:04:02How genuine was that, though? The French? We ruled the waves.
0:04:02 > 0:04:07Well, we did, but the French navy had new iron warships, steam-powered, with better guns
0:04:07 > 0:04:11and there was a genuine belief that the British navy might be beaten.
0:04:11 > 0:04:15- So this was about a massive deterrent. Shock and awe.- It is.
0:04:15 > 0:04:21It was built to resist the French, but also to deter an invader. "Come and have a go if you're hard enough."
0:04:21 > 0:04:26'Cliffe was equivalent to our nuclear deterrent today,
0:04:26 > 0:04:32'but deterrents can become obsolete incredibly quickly. Once state of the art, it's now being attacked,
0:04:32 > 0:04:38'but the invader is not a foreign power. It's the sea, which is slowly engulfing it.'
0:04:38 > 0:04:42- Where are we going now, Peter? - Inside through the only entrance.
0:04:42 > 0:04:48- Right. Why do we need these? - You'll find out in a minute. Just mind your head.
0:04:49 > 0:04:51Good grief!
0:04:53 > 0:04:56I didn't expect a fortified swamp!
0:04:56 > 0:05:03- I mean, it is like exploring some sort of jungle temple, isn't it?- Very much so.
0:05:03 > 0:05:09'Only by wading across the flooded parade ground can we get a good look at the abandoned gun emplacements,
0:05:09 > 0:05:13'which were once so vital to the nation's defence.'
0:05:13 > 0:05:18- What sort of gun would we have had in here?- An enormous gun, filling this entire space.
0:05:18 > 0:05:23It's known as a rifle muzzle loader, which means everything it fired
0:05:23 > 0:05:28- had to be loaded down the muzzle end, not the breach end. - That's quite antiquated.
0:05:28 > 0:05:34- Everything was getting industrialised.- We're on the eve of major changes in artillery.
0:05:34 > 0:05:38By the time this fort is completely built and armed with its guns,
0:05:38 > 0:05:42it's obsolete and so by the time you get to the First World War,
0:05:42 > 0:05:49which isn't that many decades away, all its guns have actually been moved up to the top of the rampart
0:05:49 > 0:05:53and these floors would have been empty.
0:05:53 > 0:05:58'Photos clearly show where the circular gun emplacements would have been,
0:05:58 > 0:06:02'but they also reveal what looks like a snip in the shoreline.
0:06:02 > 0:06:07'Research has shown this is, in fact, the unique remains of a military experiment, a world first,
0:06:07 > 0:06:11'that helped cement the Hoo's reputation for innovation.'
0:06:11 > 0:06:17- It looks like some sort of slipway. - That's indeed what it is, but it's more exciting than that.
0:06:17 > 0:06:20This is a Brennan torpedo launch rail.
0:06:20 > 0:06:27You can see this iron railway track running down from the fort and down and into the river.
0:06:27 > 0:06:32- And down this was launched a wire-guided torpedo.- Wire-guided?
0:06:32 > 0:06:38This is cutting-edge technology, the world's first operational wire-guided torpedo.
0:06:38 > 0:06:42- A guided weapons system right here on the Thames.- Yep.
0:06:42 > 0:06:48So the idea is you're attacking shipping. There's some sighting mechanism?
0:06:48 > 0:06:54That's right. An observation post inside the fort, when it observed the enemy was in the river,
0:06:54 > 0:06:59it launched the torpedo down this rail, it slides down, hits the water
0:06:59 > 0:07:04- and then its propulsion mechanism kicks in.- There were large targets.
0:07:04 > 0:07:11- Presumably it was never used in anger.- Never in anger, but it has got the record of sinking a ship.
0:07:11 > 0:07:16Just as you can see a large commercial ship coming up the Thames,
0:07:16 > 0:07:24in 1901 a small coastal ketch was doing the same and this torpedo station was carrying out trials
0:07:24 > 0:07:30and launched its torpedo and, horror of horrors, struck and sank the ship. A British ship.
0:07:30 > 0:07:37- Oh! The form filling! Was anyone hurt?- No, thankfully they were able to abandon ship
0:07:37 > 0:07:41and were rescued and, indeed, the boat was later refloated.
0:07:41 > 0:07:46And at least it proved the principle worked. These things would have been effective.
0:07:46 > 0:07:52It was a hell of a way to do so, but it showed this was a workable system.
0:07:52 > 0:07:58'Developed in the 1890s, the Brennan torpedo is a great example of the Hoo's ground-breaking past,
0:07:58 > 0:08:02'but like many of the historic remains here, it's vulnerable.
0:08:02 > 0:08:08'The structure is already being washed away by the sea, so recording it is a priority,
0:08:08 > 0:08:12'but the sea isn't the only threat to the Hoo. There are also proposals
0:08:12 > 0:08:18'for a new London airport and major housing developments, one on this site,
0:08:18 > 0:08:21'where Chattenden Barracks once stood.
0:08:21 > 0:08:25'In the fields nearby, something very interesting was discovered.'
0:08:25 > 0:08:30It might just look like a piece of green hillside today,
0:08:30 > 0:08:34but this is a piece of landscape posing questions for archaeology.
0:08:34 > 0:08:39Under the right conditions, there's a whole load of different shapes, twists and turns.
0:08:39 > 0:08:43Something has been excavated in that field.
0:08:43 > 0:08:47'Until the survey, no one knew there was anything in these fields.
0:08:47 > 0:08:53'Now there's a theory they were used for experimenting with trench warfare during WWI.
0:08:53 > 0:08:55'I'm going to try and confirm that.'
0:08:58 > 0:09:03This hillside is a classic example of why aerial photography is so important
0:09:03 > 0:09:06in finding traces of the past.
0:09:06 > 0:09:09There are a few vague hints of something going on here,
0:09:09 > 0:09:16but you can't make any sense of it on the ground. But the photographs tell a completely different story.
0:09:16 > 0:09:23What these have shown is an extensive network of trenches covering more than 200 acres.
0:09:23 > 0:09:27But what's surprising is the sheer variety of trench patterns.
0:09:27 > 0:09:32There's a chance that this area was being used not just to practise trench digging,
0:09:32 > 0:09:36but to explore different types of trench design.
0:09:36 > 0:09:42World War One got bogged down in trench warfare because of technological advances,
0:09:42 > 0:09:48such as the machine gun. Traditional tactics like cavalry charges were now suicidal.
0:09:48 > 0:09:54Neither side could advance, so they dug in. It was a new type of warfare.
0:09:54 > 0:10:00The general view today is that troops were thrown into battle with very little training,
0:10:00 > 0:10:06but if we can prove the army was using these trenches to experiment with trench design
0:10:06 > 0:10:10and trained soldiers, we will have to rethink that.
0:10:12 > 0:10:17These reconstructed WWI trenches in Suffolk give an idea of what Chattenden might have looked like
0:10:17 > 0:10:20during the war.
0:10:20 > 0:10:24You wouldn't want to step up there cos your head's exposed.
0:10:24 > 0:10:30'Martin Brown has studied trenches on the battlefront, but it's the first time he's seen photos
0:10:30 > 0:10:36'of Chattenden. I also want him to look at a map of the area from 1915.
0:10:36 > 0:10:38'The date is very significant.'
0:10:38 > 0:10:45It says here, "New field works ground coloured pink". Well, that's this area here.
0:10:45 > 0:10:51And that's precisely the area where these vague crop marks are showing up.
0:10:51 > 0:10:57- "New field works", that suggests to me field works, entrenchments, excavations.- Yeah.
0:10:57 > 0:11:02The Manual of Field Works it's called. It's interesting, the date.
0:11:02 > 0:11:06You know, September '15, just a year after the war started.
0:11:06 > 0:11:10And it's the new field works ground. What have they had to do?
0:11:10 > 0:11:14Expand training, so they need more space,
0:11:14 > 0:11:20but the other thing that's really important is it's gone from a war where they'd do bits of trenching,
0:11:20 > 0:11:22for temporary position and cover,
0:11:22 > 0:11:27to, by that period, by September, 1915,
0:11:27 > 0:11:33you are into full-on trench warfare with that front that stretches all the way from Belgium to Switzerland
0:11:33 > 0:11:36and is defended every inch of the way.
0:11:36 > 0:11:42'We know that the army soon discovered that long, straight trenches were vulnerable to attack
0:11:42 > 0:11:46'and could be quickly overcome. By developing different designs,
0:11:46 > 0:11:52'such as a Greek key-like pattern of fire bays and traverses, trenches were much easier to hold.
0:11:52 > 0:11:58'Any enemy had to work its way through the zig-zag. Every twist and turn could be defended.'
0:11:58 > 0:12:04Is this more than just practice? Is this about experimentation, working out what works best?
0:12:04 > 0:12:10Yes, if you're going to see evidence of that anywhere it'll be here, on the engineers' training ground.
0:12:10 > 0:12:16They're the ones who are developing best practice. They're taking intelligence reports
0:12:16 > 0:12:21and letters coming back from the front, particularly in that first few months,
0:12:21 > 0:12:27and distilling it down into things that work, things that don't work, where you want to put your trenches.
0:12:27 > 0:12:33'And from aerial photos, Martin can link trenches he's seen on the Western Front
0:12:33 > 0:12:36'with our trenches at Chattenden.
0:12:36 > 0:12:41'So we've now got proof this really was a place where trench design was drawn up.'
0:12:41 > 0:12:45Yeah, and that's exactly what we saw at Plug Street in Belgium.
0:12:45 > 0:12:51There there's a sunken lane and Christmas '14, British troops are in there, but then what they do
0:12:51 > 0:12:57is they push forward into the field with some saps and join them up with a traversed firing line,
0:12:57 > 0:13:00exactly as you can see here.
0:13:00 > 0:13:07This is really interesting. We didn't know about this area before and the trenches they were building.
0:13:07 > 0:13:13It was just that area shaded pink on the map, very little documentary evidence, but now we have this link
0:13:13 > 0:13:15to the Western Front.
0:13:15 > 0:13:19There is a strand of history about WWI that tells you
0:13:19 > 0:13:24that men were thrown away, thrown into action untrained,
0:13:24 > 0:13:30and actually you've got solid archaeological evidence here, on the ground, in Britain,
0:13:30 > 0:13:36and on the battlefields that actually we took it really seriously and training was paramount.
0:13:40 > 0:13:46What's fascinating is that the aerial photographs have illuminated part of our history
0:13:46 > 0:13:48which was almost forgotten.
0:13:48 > 0:13:53They weren't just practising trench building at Chattenden, they were experimenting.
0:13:53 > 0:13:58They were trying to create new ways to keep the soldiers as safe as possible,
0:13:58 > 0:14:00as effective as possible.
0:14:00 > 0:14:06It was a whole new way of doing warfare and it was invented there on those fields at Chattenden.
0:14:06 > 0:14:13But being in this trench is really sobering because you realise this isn't about crop marks
0:14:13 > 0:14:19or marks in the field. These represent people's lives, their work and their deaths.
0:14:23 > 0:14:27'And it wasn't only on the Western Front people were dying.
0:14:27 > 0:14:33'Throughout WWI, people also sacrificed their lives here on the peninsula
0:14:33 > 0:14:37'as the industrial nature of modern warfare made its impact.'
0:14:37 > 0:14:43That's one of the most extraordinary pieces of landscape I've ever seen. It looks like a film set.
0:14:43 > 0:14:49There are fragments of buildings, regular lines, earthworks. There's a very definite plan to it all.
0:14:49 > 0:14:52It's an intriguing site.
0:14:52 > 0:14:57Because much of the work undertaken on the Hoo during WWI was top secret,
0:14:57 > 0:15:04very few photographs were taken. So the aerial survey shows how these buildings relate to each other.
0:15:08 > 0:15:14There's rows of roofless buildings and then there's earthwork revetments in regular pattern,
0:15:14 > 0:15:20but the earthworks have a very, very regular appearance. There's a grand design behind this.
0:15:23 > 0:15:28What an amazing place. We've got the shells of ruined buildings,
0:15:28 > 0:15:34great earthwork mounds and these enigmatic lumps of concrete sprouting out of the ground.
0:15:34 > 0:15:39This place was obviously so important once, but now it's entirely abandoned.
0:15:39 > 0:15:45'This whole area is, in fact, the remains of a massive explosives factory.
0:15:45 > 0:15:51'Research by English Heritage is revealing exactly what and how things were manufactured here.'
0:15:51 > 0:15:58What an extraordinary landscape this is. You really feel it is secretive and out of the way.
0:15:58 > 0:16:01And there's a reason why it's such a remote location.
0:16:01 > 0:16:07This site was used to manufacture and store incredibly dangerous and incredibly explosive materials.
0:16:07 > 0:16:12You needed somewhere that was far away from where people lived,
0:16:12 > 0:16:18but also as well it's close to the river, so they could take things in and out.
0:16:18 > 0:16:22The Cliffe explosives works began life back in the 1890s
0:16:22 > 0:16:27when it was used for storing gunpowder. With the coming of WWI,
0:16:27 > 0:16:30the site underwent a huge expansion.
0:16:30 > 0:16:35What we're looking at here are layers of different buildings built at different times.
0:16:35 > 0:16:40There were explosions, parts of the site were destroyed and rebuilt.
0:16:40 > 0:16:47We're looking at a very complex layout of material here. Whereas further over, in WWI,
0:16:47 > 0:16:49there's a very different layout.
0:16:49 > 0:16:56You see how it's very regular and that was all laid out in virtually one phase
0:16:56 > 0:17:00as part of that First World War expansion.
0:17:00 > 0:17:05All these mounds are again protecting the rest of the site
0:17:05 > 0:17:09from the possible blasts that could have happened,
0:17:09 > 0:17:14from the very dangerous processes that were going on within them.
0:17:16 > 0:17:21And it's such a vast complex. It's really difficult to get a handle on it on the ground.
0:17:21 > 0:17:25- The aerial view gave you that overview of the whole site.- It does.
0:17:25 > 0:17:29On the aerial view you can really see the difference in the layout.
0:17:29 > 0:17:34We've got historic aerial photographs so we can see what happened here.
0:17:34 > 0:17:39- This piece of land was used for demolitions disposals, for example. - That's so important.
0:17:39 > 0:17:46It's not just the aerial view today. It's those historic aerial views that help reveal the layers.
0:17:46 > 0:17:52I can't imagine arriving on this site on the ground. How would you survey it without the overview?
0:17:52 > 0:17:59'It's early days, but we're beginning to get an idea of how the site developed
0:17:59 > 0:18:04'from simple storage into an extensive armaments factory during the First World War.'
0:18:04 > 0:18:10This represents the massive expansion in production of cordite, which was a propellant in firearms.
0:18:10 > 0:18:17Everything from rifles right the way up to the big guns that they had on the battleships in WWI.
0:18:17 > 0:18:23- So all those shells being fired off in the great naval battles were made here.- Well, it's the cordite,
0:18:23 > 0:18:27the propellant that makes the shells go, that's manufactured here.
0:18:29 > 0:18:35'The research at the site is also revealing stories about the people who worked here.
0:18:35 > 0:18:39'Among them was Amanda Thomas' grandmother, Minnie Rogers.'
0:18:39 > 0:18:44- What did she do here? - Well, it's unclear exactly.
0:18:44 > 0:18:48She didn't talk about it that much and sadly she died before I was born,
0:18:48 > 0:18:53but I think it was probably something to do with the cordite.
0:18:53 > 0:18:58From reports that I've read of what other young women did, perhaps packing it.
0:18:58 > 0:19:04So a job, perhaps for the first time earning money, a bit of independence, but at what a price.
0:19:04 > 0:19:09- They must have known it was dangerous work.- Absolutely.
0:19:09 > 0:19:15'In fact, the work was so dangerous that 21 people died at Cliffe,
0:19:15 > 0:19:21- 'including a workman known to Amanda's grandmother.' - It really was quite awful.
0:19:21 > 0:19:25He was scraping the corrugated iron wall of one of the workshops.
0:19:25 > 0:19:31And he was scraping with a metal chisel and it caught on the corrugated iron, caused a spark
0:19:31 > 0:19:38and caused an explosion with the nitro-glycerine that was nearby to where he was scraping.
0:19:38 > 0:19:42And he was blown out of the building
0:19:42 > 0:19:45and ended up flayed in a tree.
0:19:45 > 0:19:52That's how powerful and how dangerous the explosives were that they were dealing with on a day-to-day basis.
0:19:55 > 0:20:00Actually, the Hoo Peninsula demonstrates the power of aerial archaeology.
0:20:00 > 0:20:06It's difficult to make sense of these odd lumps of concrete, but from the air patterns emerge,
0:20:06 > 0:20:10like the explosives factory. All of this is telling a story,
0:20:10 > 0:20:14a story of great scientific endeavour, but also great tragedy.
0:20:14 > 0:20:20'We've seen how innovation on the Hoo began with the forts and progressed rapidly
0:20:20 > 0:20:24'from developing trench warfare to creating explosives for warships.
0:20:24 > 0:20:28'And we're still making new discoveries.'
0:20:28 > 0:20:31The Hoo coastline is fascinating.
0:20:31 > 0:20:37It's littered with wrecks and old jetties. And down there it looks like there's an old submarine.
0:20:39 > 0:20:42But there's one particular site that's causing a lot of excitement
0:20:42 > 0:20:45and that's where I'm off to now.
0:20:50 > 0:20:53This is Kingsnorth power station.
0:20:53 > 0:20:59Back in WWI, this landscape looked totally different. It's only the historic aerial photographs
0:20:59 > 0:21:03that have captured what was going on here in those days.
0:21:06 > 0:21:10This photo was taken years before the power stations were built.
0:21:10 > 0:21:15On it is the unmistakable shape of two colossal hangars
0:21:15 > 0:21:22because this is where, in WWI, the Royal Navy designed, tested and built their airships.
0:21:22 > 0:21:28Zeppelins were already demonstrating how effectively airships could be used for bombing.
0:21:28 > 0:21:35We know that on the peninsula they were developed for anti-submarine warfare and reconnaissance.
0:21:35 > 0:21:38It was at Kingsnorth they were put through their paces,
0:21:38 > 0:21:42but the airship hangars were dismantled decades ago.
0:21:42 > 0:21:46'What we don't know is if any other buildings from the airship days survive.
0:21:46 > 0:21:51'I'm going to see if the early photos can help me find any.'
0:21:51 > 0:21:56This is astounding. I've just come onto the industrial estate looking for fragments
0:21:56 > 0:22:00of the Royal Naval Air Service station that was here
0:22:00 > 0:22:06and there are these gigantic buildings. And they do look like the buildings they are -
0:22:06 > 0:22:10definitely the buildings on these photographs.
0:22:10 > 0:22:14These are early photographs. One hangar is still in place here
0:22:14 > 0:22:21and that would be just over in that direction, where the power station is now. Massive hangars.
0:22:21 > 0:22:29Well, this is extraordinary. They are the type of buildings I would expect to be constructed
0:22:29 > 0:22:34in sort of 1915, 1916, 1917. I think they're here to service the airships.
0:22:34 > 0:22:40They're not hangars, but engineering activities that went alongside them.
0:22:40 > 0:22:44This is fascinating. They don't survive in many places.
0:22:44 > 0:22:46They're usually swept away.
0:22:46 > 0:22:53'The trouble I've got is that the only photos I have were taken in the 1920s and '30s,
0:22:53 > 0:22:58'so I can't prove these are First World War buildings, even though my hunch is that they are.'
0:22:58 > 0:23:03They do look like airship buildings. They're magnificent, actually.
0:23:03 > 0:23:06And what a surprise! Unbelievable!
0:23:06 > 0:23:12'But one surviving building has definite links to what was once a top secret base.
0:23:12 > 0:23:18'Just a few miles from Kingsnorth, a strangely-shaped barn can be seen from the air.
0:23:18 > 0:23:24'It turns out a local farmer salvaged the timber frame roof from one of the hangars.
0:23:24 > 0:23:31'We know it's originally from Kingsnorth because distinctive Admiralty marks are on the trusses.
0:23:31 > 0:23:36'It's so rare that the 215-foot-long building is now protected.'
0:23:37 > 0:23:41- This is not your normal farm barn, is it?- No!
0:23:41 > 0:23:46It's just splendid. Those cartwheel-like roof trusses there.
0:23:47 > 0:23:51'Tina Bilbay has a particular interest in the barn.
0:23:51 > 0:23:55'Her grandfather used to work at the airship station.'
0:23:55 > 0:23:59- This building would have been familiar to your grandfather.- Yes.
0:23:59 > 0:24:03This would have been where he was working, one of the buildings.
0:24:03 > 0:24:11- He was producing hydrogen and filling the airships.- And that was a dangerous thing to do.- Very.
0:24:11 > 0:24:15Very. His wages, actually, reflect that.
0:24:15 > 0:24:21When he was put in as a hydrogen worker,
0:24:21 > 0:24:26his wages were much more than just an ordinary air mechanic.
0:24:26 > 0:24:30- So he got danger money. - Danger money, yes, indeed.
0:24:30 > 0:24:35Well, it'd flammable, it's explosive, and there were fatalities.
0:24:35 > 0:24:39People were obviously dying in their thousands at the front,
0:24:39 > 0:24:45but we sometimes forget the human cost of work here on the home front, people working with munitions,
0:24:45 > 0:24:51- experimental materials, dangerous gases. They were exposed to quite a lot of danger, too.- Well, yes.
0:24:51 > 0:24:55My grandfather died in his mid-40s
0:24:55 > 0:25:01from lung troubles. And, presumably, it was the hydrogen gas that he'd got a lungful of.
0:25:01 > 0:25:08- Probably more than one lungful. - Over a long period of time. - Over the two years he worked here.
0:25:08 > 0:25:14'Tina has a photo of her grandfather and the Kingsnorth workers taken at the end of the war.
0:25:14 > 0:25:21'This might give me the proof I've been looking for that the buildings I saw earlier are from WWI.'
0:25:21 > 0:25:26So they're all standing here. The photograph was taken at that point.
0:25:26 > 0:25:32I can see the end of the hangar. They're definitely between the two. It's that one I'm interested in.
0:25:32 > 0:25:36That's the roof of it right there. Yeah, the gable end.
0:25:36 > 0:25:40I can see the building behind it. And there's the water tower behind.
0:25:40 > 0:25:45That's incredible. So it's definitely a building of that era.
0:25:45 > 0:25:50'What's clear from all the locations I've flown over on the Hoo
0:25:50 > 0:25:55'is how dramatic the pace of change has been. A few short decades
0:25:55 > 0:25:59'and the experimental and revolutionary becomes old hat.
0:25:59 > 0:26:05'And nowhere demonstrates how military technology advanced more than my final destination.'
0:26:07 > 0:26:09We began this story at Cliffe Fort
0:26:09 > 0:26:14and when it was built at the end of the 19th century, it was state-of-the-art -
0:26:14 > 0:26:20Brennan torpedoes, big guns. It was designed to protect us from attack from the sea.
0:26:20 > 0:26:23Just a few decades later, Cliffe was redundant.
0:26:23 > 0:26:28The threat now came from the air and this was the answer.
0:26:28 > 0:26:35'Because it lies in the middle of an army training ground, these buildings had lain in obscurity
0:26:35 > 0:26:39'until the aerial survey.' This is a very well laid-out site.
0:26:39 > 0:26:44Over here we've got the barracks. And this is the munitions store and officers' quarters.
0:26:44 > 0:26:49Over there is the war shelter. They went there if under attack.
0:26:49 > 0:26:53'It was thought it could be a WWII anti-aircraft battery,
0:26:53 > 0:26:59'but further investigation has revealed it's far earlier than that and dates from the First World War.
0:26:59 > 0:27:03'Its role - to defend against German bombers and zeppelins.
0:27:03 > 0:27:07'And it has a unique place in military history.'
0:27:07 > 0:27:12This is Britain's first purpose-built anti-aircraft gun emplacement.
0:27:12 > 0:27:18There's a thick concrete wall around the outside and where the gun was sited is right here.
0:27:18 > 0:27:23We've got the Thames Estuary, Cliffe over there, the munitions factory,
0:27:23 > 0:27:27Kingsnorth, the power station, the airship station just over there.
0:27:27 > 0:27:33We've got a big naval ordnance depot just over the hill. All these places had to be protected
0:27:33 > 0:27:35and this was the spot to do it from.
0:27:35 > 0:27:41'Discoveries being made on the Hoo are changing our perceptions of the First World War.
0:27:41 > 0:27:49'We're realising that research and innovation at home was every bit as vital to the success of the war
0:27:49 > 0:27:52'as the battles on the Western Front.'
0:27:52 > 0:27:58There was a time when people thought of the Hoo Peninsula as a forgotten backwater, but we've discovered
0:27:58 > 0:28:05that this place was at the centre of military technology. Trench design, airship construction,
0:28:05 > 0:28:09innovation in explosives all took place here
0:28:09 > 0:28:14and they had a profound effect on the course of World War One.
0:28:14 > 0:28:19This is a place that's embraced change and is facing change again,
0:28:19 > 0:28:24but let's hope that this change doesn't erase the traces of its heritage.
0:28:24 > 0:28:28The Hoo really is a very, very special place.
0:28:50 > 0:28:52Subtitles by Red Bee Media Ltd