The Thames: Secret War The Flying Archaeologist

Nothing in our landscape is here by accident. It's all part of the incredible story

of how people have shaped our country over thousands of years.

Every ridge, every bump has a meaning.

I'm Ben Robinson. As an archaeologist it's my job to unpick the great story we've inherited.

From my perspective, the best way to do that is up here in the air.

Aerial photography is challenging our views of some of our most iconic landscapes.

I'm flying along the Thames to find a part of our military history that was lost in just a few generations.

Is it possible that experimental research carried out here helped to change the course of WWI?

The history of the Thames and the history of the defence of Britain are intertwined,

yet there's one important part of that story that's been largely overlooked. It all took place

in an area many people have never even heard of.

We're flying over the Dartford Crossing.

We've got Essex on my left, Kent on my right, but we're heading

to the Hoo Peninsula. Down this way.

The Hoo sits on the Kent coast, flanked by the Thames to its north and the River Medway to its south.

Over the past 150 years, this place has played a major role in British military history.

It seems incredible, yet many stories of the breakthroughs that happened here have been forgotten.

Until now we've been missing a key chapter in the history of the First World War.

For while decisions of state were made miles upstream at Westminster,

it was here in what Dickens called "the wild, flat marshes"

that the dirty, gritty, industrial nature of modern warfare was being forged.

Much of the work done here was top secret. Very few records were kept.

Archaeologists at English Heritage have been carrying out the first survey of the whole peninsula,

recording every lump of concrete, every mound, from the air.

So now we can begin to piece together the untold story of exactly what went on here on the Hoo.

And I want to uncover those secrets, find out how people lived, worked, sometimes died here,

right here on the home front.

It doesn't take long to see this area has a rich military past.

The lower reaches of the Thames are punctuated by a defensive ring of coastal forts

going back centuries. They were built to repel any attacker heading up river to the capital.

Some were still in use during WWI.

Today many are abandoned and decaying so it's a race against time to research and record them.

The best way to see them in context is from the air.

From here you can see how the whole network of forts fits together.

They're really quite close.

It's difficult to imagine how a ship could get between them without being hit.

From the aerial survey, it was immediately clear that Cliffe Fort on the Thames shoreline of the Hoo

is at particular risk. It also has some unusual features.

Archaeologists are now investigating it fully for the first time.

'Peter Kendall from English Heritage is one of those carrying out the work.'

It was built in the middle of the 19th century after a Royal Commission called by Lord Palmerston.

There was a genuine belief that the French would possibly invade us.

How genuine was that, though? The French? We ruled the waves.

Well, we did, but the French navy had new iron warships, steam-powered, with better guns

and there was a genuine belief that the British navy might be beaten.

-So this was about a massive deterrent. Shock and awe.

-It is.

It was built to resist the French, but also to deter an invader. "Come and have a go if you're hard enough."

'Cliffe was equivalent to our nuclear deterrent today,

'but deterrents can become obsolete incredibly quickly. Once state of the art, it's now being attacked,

'but the invader is not a foreign power. It's the sea, which is slowly engulfing it.'

-Where are we going now, Peter?

-Inside through the only entrance.

-Right. Why do we need these?

-You'll find out in a minute. Just mind your head.

Good grief!

I didn't expect a fortified swamp!

-I mean, it is like exploring some sort of jungle temple, isn't it?

-Very much so.

'Only by wading across the flooded parade ground can we get a good look at the abandoned gun emplacements,

'which were once so vital to the nation's defence.'

-What sort of gun would we have had in here?

-An enormous gun, filling this entire space.

It's known as a rifle muzzle loader, which means everything it fired

-had to be loaded down the muzzle end, not the breach end.

-That's quite antiquated.

-Everything was getting industrialised.

-We're on the eve of major changes in artillery.

By the time this fort is completely built and armed with its guns,

it's obsolete and so by the time you get to the First World War,

which isn't that many decades away, all its guns have actually been moved up to the top of the rampart

and these floors would have been empty.

'Photos clearly show where the circular gun emplacements would have been,

'but they also reveal what looks like a snip in the shoreline.

'Research has shown this is, in fact, the unique remains of a military experiment, a world first,

'that helped cement the Hoo's reputation for innovation.'

-It looks like some sort of slipway.

-That's indeed what it is, but it's more exciting than that.

This is a Brennan torpedo launch rail.

You can see this iron railway track running down from the fort and down and into the river.

-And down this was launched a wire-guided torpedo.

-Wire-guided?

This is cutting-edge technology, the world's first operational wire-guided torpedo.

-A guided weapons system right here on the Thames.

-Yep.

So the idea is you're attacking shipping. There's some sighting mechanism?

That's right. An observation post inside the fort, when it observed the enemy was in the river,

it launched the torpedo down this rail, it slides down, hits the water

-and then its propulsion mechanism kicks in.

-There were large targets.

-Presumably it was never used in anger.

-Never in anger, but it has got the record of sinking a ship.

Just as you can see a large commercial ship coming up the Thames,

in 1901 a small coastal ketch was doing the same and this torpedo station was carrying out trials

and launched its torpedo and, horror of horrors, struck and sank the ship. A British ship.

-Oh! The form filling! Was anyone hurt?

-No, thankfully they were able to abandon ship

and were rescued and, indeed, the boat was later refloated.

And at least it proved the principle worked. These things would have been effective.

It was a hell of a way to do so, but it showed this was a workable system.

'Developed in the 1890s, the Brennan torpedo is a great example of the Hoo's ground-breaking past,

'but like many of the historic remains here, it's vulnerable.

'The structure is already being washed away by the sea, so recording it is a priority,

'but the sea isn't the only threat to the Hoo. There are also proposals

'for a new London airport and major housing developments, one on this site,

'where Chattenden Barracks once stood.

'In the fields nearby, something very interesting was discovered.'

It might just look like a piece of green hillside today,

but this is a piece of landscape posing questions for archaeology.

Under the right conditions, there's a whole load of different shapes, twists and turns.

Something has been excavated in that field.

'Until the survey, no one knew there was anything in these fields.

'Now there's a theory they were used for experimenting with trench warfare during WWI.

'I'm going to try and confirm that.'

This hillside is a classic example of why aerial photography is so important

in finding traces of the past.

There are a few vague hints of something going on here,

but you can't make any sense of it on the ground. But the photographs tell a completely different story.

What these have shown is an extensive network of trenches covering more than 200 acres.

But what's surprising is the sheer variety of trench patterns.

There's a chance that this area was being used not just to practise trench digging,

but to explore different types of trench design.

World War One got bogged down in trench warfare because of technological advances,

such as the machine gun. Traditional tactics like cavalry charges were now suicidal.

Neither side could advance, so they dug in. It was a new type of warfare.

The general view today is that troops were thrown into battle with very little training,

but if we can prove the army was using these trenches to experiment with trench design

and trained soldiers, we will have to rethink that.

These reconstructed WWI trenches in Suffolk give an idea of what Chattenden might have looked like

during the war.

You wouldn't want to step up there cos your head's exposed.

'Martin Brown has studied trenches on the battlefront, but it's the first time he's seen photos

'of Chattenden. I also want him to look at a map of the area from 1915.

'The date is very significant.'

It says here, "New field works ground coloured pink". Well, that's this area here.

And that's precisely the area where these vague crop marks are showing up.

-"New field works", that suggests to me field works, entrenchments, excavations.

-Yeah.

The Manual of Field Works it's called. It's interesting, the date.

You know, September '15, just a year after the war started.

And it's the new field works ground. What have they had to do?

Expand training, so they need more space,

but the other thing that's really important is it's gone from a war where they'd do bits of trenching,

for temporary position and cover,

to, by that period, by September, 1915,

you are into full-on trench warfare with that front that stretches all the way from Belgium to Switzerland

and is defended every inch of the way.

'We know that the army soon discovered that long, straight trenches were vulnerable to attack

'and could be quickly overcome. By developing different designs,

'such as a Greek key-like pattern of fire bays and traverses, trenches were much easier to hold.

'Any enemy had to work its way through the zig-zag. Every twist and turn could be defended.'

Is this more than just practice? Is this about experimentation, working out what works best?

Yes, if you're going to see evidence of that anywhere it'll be here, on the engineers' training ground.

They're the ones who are developing best practice. They're taking intelligence reports

and letters coming back from the front, particularly in that first few months,

and distilling it down into things that work, things that don't work, where you want to put your trenches.

'And from aerial photos, Martin can link trenches he's seen on the Western Front

'with our trenches at Chattenden.

'So we've now got proof this really was a place where trench design was drawn up.'

Yeah, and that's exactly what we saw at Plug Street in Belgium.

There there's a sunken lane and Christmas '14, British troops are in there, but then what they do

is they push forward into the field with some saps and join them up with a traversed firing line,

exactly as you can see here.

This is really interesting. We didn't know about this area before and the trenches they were building.

It was just that area shaded pink on the map, very little documentary evidence, but now we have this link

to the Western Front.

There is a strand of history about WWI that tells you

that men were thrown away, thrown into action untrained,

and actually you've got solid archaeological evidence here, on the ground, in Britain,

and on the battlefields that actually we took it really seriously and training was paramount.

What's fascinating is that the aerial photographs have illuminated part of our history

which was almost forgotten.

They weren't just practising trench building at Chattenden, they were experimenting.

They were trying to create new ways to keep the soldiers as safe as possible,

as effective as possible.

It was a whole new way of doing warfare and it was invented there on those fields at Chattenden.

But being in this trench is really sobering because you realise this isn't about crop marks

or marks in the field. These represent people's lives, their work and their deaths.

'And it wasn't only on the Western Front people were dying.

'Throughout WWI, people also sacrificed their lives here on the peninsula

'as the industrial nature of modern warfare made its impact.'

That's one of the most extraordinary pieces of landscape I've ever seen. It looks like a film set.

There are fragments of buildings, regular lines, earthworks. There's a very definite plan to it all.

It's an intriguing site.

Because much of the work undertaken on the Hoo during WWI was top secret,

very few photographs were taken. So the aerial survey shows how these buildings relate to each other.

There's rows of roofless buildings and then there's earthwork revetments in regular pattern,

but the earthworks have a very, very regular appearance. There's a grand design behind this.

What an amazing place. We've got the shells of ruined buildings,

great earthwork mounds and these enigmatic lumps of concrete sprouting out of the ground.

This place was obviously so important once, but now it's entirely abandoned.

'This whole area is, in fact, the remains of a massive explosives factory.

'Research by English Heritage is revealing exactly what and how things were manufactured here.'

What an extraordinary landscape this is. You really feel it is secretive and out of the way.

And there's a reason why it's such a remote location.

This site was used to manufacture and store incredibly dangerous and incredibly explosive materials.

You needed somewhere that was far away from where people lived,

but also as well it's close to the river, so they could take things in and out.

The Cliffe explosives works began life back in the 1890s

when it was used for storing gunpowder. With the coming of WWI,

the site underwent a huge expansion.

What we're looking at here are layers of different buildings built at different times.

There were explosions, parts of the site were destroyed and rebuilt.

We're looking at a very complex layout of material here. Whereas further over, in WWI,

there's a very different layout.

You see how it's very regular and that was all laid out in virtually one phase

as part of that First World War expansion.

All these mounds are again protecting the rest of the site

from the possible blasts that could have happened,

from the very dangerous processes that were going on within them.

And it's such a vast complex. It's really difficult to get a handle on it on the ground.

-The aerial view gave you that overview of the whole site.

-It does.

On the aerial view you can really see the difference in the layout.

We've got historic aerial photographs so we can see what happened here.

-This piece of land was used for demolitions disposals, for example.

-That's so important.

It's not just the aerial view today. It's those historic aerial views that help reveal the layers.

I can't imagine arriving on this site on the ground. How would you survey it without the overview?

'It's early days, but we're beginning to get an idea of how the site developed

'from simple storage into an extensive armaments factory during the First World War.'

This represents the massive expansion in production of cordite, which was a propellant in firearms.

Everything from rifles right the way up to the big guns that they had on the battleships in WWI.

-So all those shells being fired off in the great naval battles were made here.

-Well, it's the cordite,

the propellant that makes the shells go, that's manufactured here.

'The research at the site is also revealing stories about the people who worked here.

'Among them was Amanda Thomas' grandmother, Minnie Rogers.'

-What did she do here?

-Well, it's unclear exactly.

She didn't talk about it that much and sadly she died before I was born,

but I think it was probably something to do with the cordite.

From reports that I've read of what other young women did, perhaps packing it.

So a job, perhaps for the first time earning money, a bit of independence, but at what a price.

-They must have known it was dangerous work.

-Absolutely.

'In fact, the work was so dangerous that 21 people died at Cliffe,

-'including a workman known to Amanda's grandmother.'

-It really was quite awful.

He was scraping the corrugated iron wall of one of the workshops.

And he was scraping with a metal chisel and it caught on the corrugated iron, caused a spark

and caused an explosion with the nitro-glycerine that was nearby to where he was scraping.

And he was blown out of the building

and ended up flayed in a tree.

That's how powerful and how dangerous the explosives were that they were dealing with on a day-to-day basis.

Actually, the Hoo Peninsula demonstrates the power of aerial archaeology.

It's difficult to make sense of these odd lumps of concrete, but from the air patterns emerge,

like the explosives factory. All of this is telling a story,

a story of great scientific endeavour, but also great tragedy.

'We've seen how innovation on the Hoo began with the forts and progressed rapidly

'from developing trench warfare to creating explosives for warships.

'And we're still making new discoveries.'

The Hoo coastline is fascinating.

It's littered with wrecks and old jetties. And down there it looks like there's an old submarine.

But there's one particular site that's causing a lot of excitement

and that's where I'm off to now.

This is Kingsnorth power station.

Back in WWI, this landscape looked totally different. It's only the historic aerial photographs

that have captured what was going on here in those days.

This photo was taken years before the power stations were built.

On it is the unmistakable shape of two colossal hangars

because this is where, in WWI, the Royal Navy designed, tested and built their airships.

Zeppelins were already demonstrating how effectively airships could be used for bombing.

We know that on the peninsula they were developed for anti-submarine warfare and reconnaissance.

It was at Kingsnorth they were put through their paces,

but the airship hangars were dismantled decades ago.

'What we don't know is if any other buildings from the airship days survive.

'I'm going to see if the early photos can help me find any.'

This is astounding. I've just come onto the industrial estate looking for fragments

of the Royal Naval Air Service station that was here

and there are these gigantic buildings. And they do look like the buildings they are -

definitely the buildings on these photographs.

These are early photographs. One hangar is still in place here

and that would be just over in that direction, where the power station is now. Massive hangars.

Well, this is extraordinary. They are the type of buildings I would expect to be constructed

in sort of 1915, 1916, 1917. I think they're here to service the airships.

They're not hangars, but engineering activities that went alongside them.

This is fascinating. They don't survive in many places.

They're usually swept away.

'The trouble I've got is that the only photos I have were taken in the 1920s and '30s,

'so I can't prove these are First World War buildings, even though my hunch is that they are.'

They do look like airship buildings. They're magnificent, actually.

And what a surprise! Unbelievable!

'But one surviving building has definite links to what was once a top secret base.

'Just a few miles from Kingsnorth, a strangely-shaped barn can be seen from the air.

'It turns out a local farmer salvaged the timber frame roof from one of the hangars.

'We know it's originally from Kingsnorth because distinctive Admiralty marks are on the trusses.

'It's so rare that the 215-foot-long building is now protected.'

-This is not your normal farm barn, is it?

-No!

It's just splendid. Those cartwheel-like roof trusses there.

'Tina Bilbay has a particular interest in the barn.

'Her grandfather used to work at the airship station.'

-This building would have been familiar to your grandfather.

-Yes.

This would have been where he was working, one of the buildings.

-He was producing hydrogen and filling the airships.

-And that was a dangerous thing to do.

-Very.

Very. His wages, actually, reflect that.

When he was put in as a hydrogen worker,

his wages were much more than just an ordinary air mechanic.

-So he got danger money.

-Danger money, yes, indeed.

Well, it'd flammable, it's explosive, and there were fatalities.

People were obviously dying in their thousands at the front,

but we sometimes forget the human cost of work here on the home front, people working with munitions,

-experimental materials, dangerous gases. They were exposed to quite a lot of danger, too.

-Well, yes.

My grandfather died in his mid-40s

from lung troubles. And, presumably, it was the hydrogen gas that he'd got a lungful of.

-Probably more than one lungful.

-Over a long period of time.

-Over the two years he worked here.

'Tina has a photo of her grandfather and the Kingsnorth workers taken at the end of the war.

'This might give me the proof I've been looking for that the buildings I saw earlier are from WWI.'

So they're all standing here. The photograph was taken at that point.

I can see the end of the hangar. They're definitely between the two. It's that one I'm interested in.

That's the roof of it right there. Yeah, the gable end.

I can see the building behind it. And there's the water tower behind.

That's incredible. So it's definitely a building of that era.

'What's clear from all the locations I've flown over on the Hoo

'is how dramatic the pace of change has been. A few short decades

'and the experimental and revolutionary becomes old hat.

'And nowhere demonstrates how military technology advanced more than my final destination.'

We began this story at Cliffe Fort

and when it was built at the end of the 19th century, it was state-of-the-art -

Brennan torpedoes, big guns. It was designed to protect us from attack from the sea.

Just a few decades later, Cliffe was redundant.

The threat now came from the air and this was the answer.

'Because it lies in the middle of an army training ground, these buildings had lain in obscurity

'until the aerial survey.' This is a very well laid-out site.

Over here we've got the barracks. And this is the munitions store and officers' quarters.

Over there is the war shelter. They went there if under attack.

'It was thought it could be a WWII anti-aircraft battery,

'but further investigation has revealed it's far earlier than that and dates from the First World War.

'Its role - to defend against German bombers and zeppelins.

'And it has a unique place in military history.'

This is Britain's first purpose-built anti-aircraft gun emplacement.

There's a thick concrete wall around the outside and where the gun was sited is right here.

We've got the Thames Estuary, Cliffe over there, the munitions factory,

Kingsnorth, the power station, the airship station just over there.

We've got a big naval ordnance depot just over the hill. All these places had to be protected

and this was the spot to do it from.

'Discoveries being made on the Hoo are changing our perceptions of the First World War.

'We're realising that research and innovation at home was every bit as vital to the success of the war

'as the battles on the Western Front.'

There was a time when people thought of the Hoo Peninsula as a forgotten backwater, but we've discovered

that this place was at the centre of military technology. Trench design, airship construction,

innovation in explosives all took place here

and they had a profound effect on the course of World War One.

This is a place that's embraced change and is facing change again,

but let's hope that this change doesn't erase the traces of its heritage.

The Hoo really is a very, very special place.

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