Making Connections Dreaming the Impossible: Unbuilt Britain

The amazing structures that surround us -

the bridges, towers and great public buildings -

all have a story to tell.

Behind nearly every one of these triumphs

is an untold drama of a world that might have been.

In this series, I'm exploring ambitious ventures by some of our greatest architects and engineers

but which ultimately remained on the drawing board.

Travelling to France, I'll uncover the story of a daring

engineer who risked his life for a Channel crossing

but he died having built nothing.

And I'll discover why events leading up to the First World War

might have turned the north of Scotland into an off-shore island.

This is a story of international relations...

..of canals, tunnels and changing attitude...

and of an island nation in fear of opening the front door to her neighbours.

Welcome to the remarkable world of Unbuilt Britain.

By profession, I'm an architectural historian

and I spend a lot of time searching for evidence that throws light

on the buildings of the past.

My research tells me that history is littered with failed grand designs

and the archives are full of bold schemes that were never built.

I want to find out why.

There are different kinds of unbuilt projects.

Some are so visionary,

you can see in later built works where those inspirations came from.

Tracing this history of the unbuilt leads to some extraordinary engineering schemes.

There have been countless plans over the years to connect mainland Britain to the outside world.

In the 19th century, there were proposals for a tunnel to Ireland,

an idea that has never entirely been taken off the table.

There was even an idea for a great belt railway

that would have spanned the world, all the way to Australia.

Projects on such a grand scale often fall victim to the politics of their age.

And the two schemes that I want to investigate are typically full of intrigue and beset by xenophobia.

Before the First World War,

fear of invasion inspired a bold idea to drive a sea lane

the size of the Panama Canal through the heart of Scotland.

Known as the Mid-Scotland Ship Canal,

it would have cut the country in half.

But first, I'll discover how early unbuilt plans for a Channel Tunnel

ultimately helped to make that fixed link

between Britain and France possible.

This exploration of unbuilt Britain involves a train journey from London

through a tunnel under the English Channel to Paris.

20 years ago, such a trip wouldn't have been possible.

But now, more than 27,000 people travel between France and Britain by train every day.

And it's on the other side of the Channel that our story begins.

Thanks to the Channel Tunnel that opened in 1994,

we now have a fixed connection from the heart of London to France and beyond.

We're just approaching the tunnel now.

These 31 miles of tunnel under the Channel took eight years to build.

The momentous breakthrough, linking France and Britain,

came at 11 o'clock on the 1st December 1990,

when the last wall of rock fell.

They're through! They're through!

They're through, hey!

But it had been a very long time coming.

For over 200 years, the hopes of engineers and architects

had been thwarted by a turbulent history and the fear of invasion.

Curiously, the first known plan for a fixed link across the Channel

was actually conceived in the middle of a Continental war.

The year was 1802.

Napoleon's armies had been ravaging mainland Europe for almost a decade.

Napoleon had armies at Boulogne and at Cherbourg and at Flushing

and was planning to invade England. This was the nightmare scenario.

This was the darkest hour of England's history,

when we stood alone against this overwhelming enemy.

To conceive a plan to link the two countries permanently

at this time required a serious leap of the imagination.

But the man with that early vision, Albert Mathieu-Favier,

believed in a better world.

Taking advantage of a lull in hostilities,

Mathieu-Favier designed a tunnel that would allow travellers

to avoid the stormy waters of the Channel

and speed up the journey time between London and Paris.

Mathieu-Favier's idea was for a single tunnel dug under the Channel.

It was designed for use by horse-drawn stagecoaches

and had tall ventilation chimneys reaching high above the waves.

Napoleon Bonaparte was said to like the idea,

but the British were suspicious,

thoroughly convinced that this was a cunning plan for French invasion.

Mathieu-Favier undoubtedly had ideas ahead of his time.

But unlike the buildings behind me, the peace of the day was not built to last.

By May of 1803, Britain and France were enemies once again

and his plans, whether drawn up in peace time or otherwise, were forgotten.

The demise of Mathieu-Favier's plan is an augury

for the future direction of our tale.

The very idea of building a tunnel brought out the worst,

rabid, xenophobic, anti-French reactions imaginable.

France was an inveterate, long-term, permanent enemy.

Building a tunnel linking England and France was just inviting trouble.

The story of the Channel Tunnel is a mirror of European history

and, in particular, the ever-shifting relations between France and Britain

through war, enmity and finally peace.

It would take nearly 200 years

and dozens of unbuilt plans to realise the dream.

And Mathieu-Favier was just one in a long line of daring engineers

who would try to complete this Herculean project.

If Mathieu-Favier can be marked down as a bit of a visionary,

then the next man in line,

Monsieur Louis Joseph Aime Thome de Gamond,

not only had a grandiloquent name, but he clearly had the ambition to match.

This man was the original Chunnel pioneer.

Born in Poitiers in 1807, Thome de Gamond

was a highly educated man with doctorates in medicine and law.

But de Gamond's real passion lay under the sea.

A generation after Mathieu-Favier had dreamt of a tunnel beneath the Channel,

de Gamond devoted his life to the idea of a permanent link between Britain and France.

I've come to the Bibliotheque Nationale in Paris

to find out more about de Gamond's pioneering research

from historian Laurent Bonnaud.

I think what set him apart from his peers was his scientific mind

and the continuity in his surveying and research.

He was very early in thinking about cross-Channel fixed links

and he was extremely scientific in his way of doing things.

He was systematic. He was very rigorous.

He really put all his means, all his...everything he had,

in terms of time,

finances and even taking physical risks into his project.

In 1833, Thome de Gamond's lifelong study of a Channel crossing began.

He didn't just imagine a tunnel linking England and France.

His initial ideas included a cast iron tube laid along the sea bed.

The trains would travel simply through this tube,

but it was not realistic due to the streams,

the very strong streams, through the Channel.

After ruling out eight other methods,

de Gamond was finally convinced that a tunnel was the way forward.

But to proceed, he had to establish

if the rocks beneath the waves were suitable for tunnelling.

What happened next demonstrates

de Gamond's astonishing level of commitment to his cause.

Risking all, the 48-year-old Frenchman took a deep breath

and dropped into the freezing waters of the Channel.

This was long before modern diving techniques had been developed

and de Gamond had no means of breathing beneath the waves.

Weighed down with bags filled with 86 kilos of flint stones,

and with his ears protected from the immense water pressure

by pads of buttered lint,

de Gamond sank to a depth of over 30 metres

to carry out the first recorded survey of the Channel sea bed.

There he fought off strong currents and creatures of the deep.

He used cloth around the neck to protect himself from being bitten

by conger eels or such fishes, which happened to him, actually.

It was really not sophisticated at all.

-And at quite a considerable personal danger.

-And it was also very cold.

Despite these incredibly adverse conditions,

de Gamond managed to return from the sea bed with rock samples

that would prove to be hugely important.

Thome de Gamond discovered that there was a continuity

of chalk layers from the Jurassic time.

The tunnel had to follow one of the layers as much as possible

in order to avoid breakthrough of water.

De Gamond's discovery was momentous

and justified the risks he'd taken to get his samples.

He had proved that the geology of the Straits of Dover

was perfect for a Channel Tunnel.

And in 1856, de Gamond drew up a detailed master plan

based on 20 years of solitary, painstaking research.

This shows us a section of the tunnel, Laurent.

What were some of its features?

It was a single tunnel with brick walls and a double railway track.

Interestingly enough, the diameter of the tunnel

was roughly seven metres, which is close to the existing tunnel.

Obviously, one of the biggest problems was how to ventilate this tunnel.

How would people breathe, travellers breathe,

through the nearly 40 kilometres?

Thome de Gamond came up with a novel solution to the ventilation problem.

On a sandbank in the Channel called Le Varne,

he proposed building an artificial island.

He called it the Etoile de Varne.

The Etoile de Varne offered the possibility to make a stop,

to make a break in the middle of the Channel,

for the travellers, by train, to get out and breathe the fresh air.

The Etoile de Varne would be the place where travellers from Europe

would meet, just in the middle of the Channel, and interact.

So it was not only a technical aspect but also a symbolic one.

So this was really a breakthrough for the Channel Tunnel studies,

and that all the subsequent schemes were based at least on things

that Thome de Gamond had realised.

Although de Gamond was a daring pioneer, there was just one problem.

No-one had dug a tunnel under the open sea before.

But on the other side of the Channel,

one project had pushed the limits of what was achievable.

In London, a tunnel had been dug not under the sea but under a river.

The Thames Tunnel is the only project on which

two members of the world-renowned Brunel family worked together.

Amazingly, the product of that pioneering father and son team

survives intact, and is still in use to this day.

Anglo-French Marc Isambard and his son,

the 19-year-old Isambard Kingdom Brunel,

began digging the world's first underwater tunnel at Rotherhithe

in 1825, just before Thome de Gamond embarked on his research.

Brunel Senior and Thome de Gamond knew one another

and de Gamond avidly followed the progress of the Thames Tunnel.

I've come to Rotherhithe to meet Robert Hulse,

the director of the Brunel Tunnel Museum.

Olivia, hello. Welcome to the eighth wonder of the world.

-Lovely to be here.

-Follow me.

Robert takes me underground to show me Brunel's remarkable engineering achievement,

a twin-track tunnel under the river.

Originally designed for horse-drawn vehicles,

the tunnel now carries London rail traffic.

-And there it is.

-The world's first underwater tunnel.

It's tremendously exciting to see the entrance to the two tunnels.

Yeah, you can see how the tunnel dips under the river,

cos Brunel is trying to get below the blue clay,

the strata of blue clay, that's impervious.

Brunel used a revolutionary technique to excavate the Thames Tunnel.

Called the tunnel shield, it was an iron cage

that protected 36 miners working at the digging face.

Each man dug a few inches of the clay in front of him,

while a gigantic screw jacked the whole structure forwards inch by inch.

Behind came the bricklayers, who lined the tunnel to make it safe.

Tunnel shields were widely adopted

and were later used extensively to dig the London Underground.

The Thames Tunnel finally opened in 1843.

Even with Brunel's innovative tunnelling shield,

it had taken 18 years to burrow

a distance of less than a quarter of a mile.

At that rate, a Channel tunnel would have taken centuries to complete.

But de Gamond was undaunted. He believed he could dig faster.

Although the Brunels had planned the tunnel

to be for the movement of cargo,

it was initially opened solely as a pedestrian tunnel,

and earned its keep as a visitor attraction,

charging a penny to enter.

On the first day, there were 50,000 visitors.

By the end of the third month, when it opened in 1843,

there were a million visitors.

-That's half the population of London...

-Astonishing!

..in the first three months.

The building of the Thames Tunnel was a staggering achievement.

The ambition required even to conceive of such a project

being possible was enormous.

Against all the odds, Brunel father and son managed to achieve what they set out to do -

to build the world's first ever underwater tunnel.

Brunel's tunnel under the Thames was absolutely ground-breaking.

They proved a point that tunnelling under waterways

was now within the ability of engineers of their time.

The tunnel was big news.

And engineers the world over were paying very close attention,

not least Thome de Gamond.

Back in France,

de Gamond was inspired by the example of the Brunels' success.

Using the techniques they'd pioneered,

he wanted to forge ahead with his own colossal Channel Tunnel project.

But he knew that to get a project linking the two nations

off the ground would require more than engineering vision.

It needed political support.

Thome de Gamond had friends in high places.

By chance, at university, he befriended a certain Prince Louis

who would later become a very important person.

De Gamond's student chum had become the first

president of the French Republic.

He was none other than Napoleon III, the nephew of Napoleon Bonaparte.

Napoleon was keen on his friend's plans.

If the English had done it under the Thames,

why not the French under the Channel?

Public opinion on both sides was warming to the idea.

Even the notoriously xenophobic British press began to make encouraging noises.

It's also said that the famously seasick Queen Victoria

supported de Gamond's scheme -

anything to avoid the queasy waters of the Channel.

Everything was in place. The plans were on the table.

A tentative trust was growing between the two nations.

Surely, nothing could stop the tunnel going ahead now?

Just as it was looking like Napoleon would give the plan the go-ahead,

an eventful trip to the Paris Opera changed everything.

Napoleon III was travelling by carriage along Rue Le Peletier

when he was set upon by a mob

led by Italian revolutionary, Felice Orsini.

Orsini's men threw bombs at the imperial carriage,

killing eight people and injuring more than 100.

Orsini and his men attempted to assassinate Napoleon

and in doing so, halted de Gamond's plans for a Channel tunnel once and for all.

Napoleon emerged unscathed

and bravely carried on to take his place in his box at the opera house,

just in time for the curtain to go up on Rossini's William Tell.

What, you may well ask, had this to do with Thome de Gamond

and his Channel tunnel?

Well, rather a lot.

Because the would-be assassin and his British-made bombs

had travelled to Paris from England via the Channel.

If an assassin could travel to France without the aid of a tunnel,

imagine how much easier it could be

in the future for enemies of the state to reach French shores.

Xenophobia and international politics had killed off de Gamond's

project to link two countries in peace and friendship.

But as with all good ideas, it wouldn't go away.

The idea of a Channel tunnel was kept alive

throughout the 19th century by the expansion of rail travel.

Across Britain and the Continent there was a civil engineering boom

and everywhere, new tunnels and bridges were helping to slash journey times.

Civil engineering in the 19th century was a game-changer.

The country was developing from, primarily,

an agricultural economy and was becoming industrialised.

So civil engineers were at the forefront of all that

and were recognised as national heroes in their time.

Here at the Institute of Civil Engineers in London,

the archives are full to bursting with plans lodged by ambitious

engineers determined to make their mark on the world.

Civil engineers like Brunel, Telford and Stevenson

drove the Industrial Revolution

and made their names building great civic infrastructure that still remains to this day.

If you could be the man to come up with a way to make

the notorious Channel crossing both faster and easier,

your name would be sure to go down in history.

I've discovered detailed plans here for all manner of Channel crossings.

An international floating tunnel, a cast iron tube, a bridge

and countless designs for tunnels of varying shapes and sizes.

Amongst all these plans by aspiring British engineers,

I've uncovered something of an unexpected gem.

This is a first edition copy of Thome de Gamond's

plans for the Channel Tunnel.

But it's a particularly special copy because here at the front,

just tipped in, is a letter from Thome de Gamond himself,

presenting this book to the library.

And in it he talks about his hopes for the project of the Channel Tunnel.

He describes how he wants the great obstacles that exist to be overcome.

And he also describes the idea of a tunnel itself as something

which would be both useful and also glorious.

Although the assassination attempt on Napoleon had soured relations

between the governments of France and Britain,

it hadn't stopped an understanding evolving amongst the engineers of the day.

Perhaps the international language of science and technology

could succeed where the politics of suspicion had failed.

In 1868, the Channel Tunnel baton was passed to a Scottish mining engineer,

William Lowe, who'd studied de Gamond's plans.

Recognising their brilliance, Lowe built on the Frenchman's achievements

and came up with a scheme of his own.

This is an image of William Lowe's plan.

It's meticulously drawn, which doubtless helped to sell it

as a project to the people who looked at it.

And what's astonishing is that even though this was produced in 1868,

it's essentially the same type of scheme

that we have for the Channel Tunnel today.

Lowe's plan was beautifully simple.

It involved two single-bore tunnels, each with a railway track.

The two were interconnected by a ventilation system

based on those he'd developed for mining tunnels.

His tunnel was to run 23 miles

from Dover to Calais,

right through the layer of chalk discovered by Thome de Gamond.

Before his death in 1876, de Gamond actually wrote to Lowe.

He gave the Scotsman his blessing,

saying he'd always hoped to collaborate

with a colleague from across the Channel.

Lowe was undoubtedly a brilliant engineer,

but for his plan to succeed where others had failed,

he needed money and influence.

Step in Sir Edward Watkin.

The Richard Branson of his day,

Watkin was a flamboyant rail entrepreneur and MP.

An ambitious man with powerful allies in government.

Sir Edward Watkin was the last of the railway kings.

A very vigorous man

and he called a spade a spade.

He was a Mancunian and...he was a very imaginative man

in the sense of, like a lot of Victorians,

he thought that if a thing was sound in theory, it would work in practice.

Watkin was a shrewd businessman with an eye on the next big thing.

William Lowe's Channel Tunnel design

was just what he was after.

He's looking at building a railway link that essentially goes

from the Midlands and further North,

all the way through Southern England,

through a tunnel into France and tapping a massive market,

and thinks that it's a goer.

This is Abbot's Cliff between Dover and Folkestone.

I've come to see for myself how the unbuilt almost happened.

Here in 1880, thanks to Lowe's vision and Watkin's money,

the business of tunnelling started for the first time

in the project's history. They began to dig.

Edward Watkin employed a team of Welsh miners.

Carving through the white chalk,

they began to sink the first shaft for a tunnel to France.

Joining me is foreign policy expert, Professor Amelia Hadfield,

who understands the politics of the day.

So we're off to find the spot

where they actually started digging in 1880.

What had enabled them to begin that at that point?

Well, you have a blossoming, I think, of relationships

based on diplomatic agreements between, between England and France,

and, fundamentally, you have the English Channel Tunnel Company Bill,

being set before the, the House of Commons, and also the French National Assembly.

Just a few yards further along the shore line,

under the famous White Cliffs,

is the place where Watkin's men set to work on this epic undertaking.

This doesn't look like a site of huge historical significance, does it, Amelia?

But, but this is actually the point

where they started tunnelling, here, at Abbot's Cliff.

And inside there, is the beginning of the tunnel.

Yes, exactly. I know it looks a little unprepossessing,

but this is, in fact, a very historical place in British history,

in French history as well, to the point.

This is where, this is where it all began,

so you have to, I think, try to imagine beyond the door.

Although Watkin's tunnel remains within the cliffs,

a recent collapse means it's too dangerous for us to go inside.

But a valuable newsreel gives an insight

into what lies behind the door.

'Near Dover, the old workings are still regularly inspected.

'This was the start of the pilot tunnel, begun about 1880.'

This tunnel was excavated by Watkin's team using a boring machine

based on the same principle as Brunel's tunnelling shield.

At the same time,

a French team on the other side of the Channel dug to meet them.

Conscious of sensitive public opinion,

Watkin promoted the project,

throwing banquets and arranging underground visits

for the VIPs and celebrities of the day.

He certainly had a PR, a savvy streak in him,

which would seem very contemporary to us now.

He was smart enough to, to bring a few of the great and the good,

like Gladstone, for example, the Prince of Wales

and also the Archbishop of Canterbury,

and give them private tours,

and I think, in that sense, sort of an inculcator,

a degree of legitimacy about the whole project.

But while Watkin and his friends were partying below the Channel,

things above ground were beginning to take a turn for the worse.

The War Office got involved

and realised perhaps the security implications,

obviously, the strategic implications,

and you just have to look around here to get a sense, obviously,

that you're boring into, to the side of the cliff of a sovereign state

with the intention of constructing a subterranean tunnel

to another sovereign state.

More to the point, I think,

is the public outcry that you get surprisingly quickly,

and with a very sort of poisonous feel to it.

In 1882, the front windows of the British Channel Tunnel Company are smashed,

because of the problems that the British population at this point feel

with regards to building a tunnel that can in no way guarantee the security of the island.

And Watkin, whose tunnel this is in many ways, is demonised.

And when the upper classes joined the voices of opposition,

it seemed that Watkin had at last met his match.

A powerful petition was mounted against the project.

In this petition, you see a gathering together of public opinion

stretching from the Cabinet right down to the man on the Clapham omnibus,

and all them voice opposition and, in some sense, real venom

with regards to the problems that could arise

should relations between the two countries turn sour at any point.

Faced with a groundswell of opposition

and grave warnings from the War Office,

the government gave in and, in 1882, digging was stopped.

Watkin and Lowe's dream of a tunnel under the Channel was at an end.

It would be almost a century before a Channel Tunnel project

was seriously considered again.

Yet again, Britain's xenophobic instincts had won the day.

The fraught relationship between Britain and the continent

had stymied the cross-Channel accord between engineers.

Deep underground, there's a telling footnote to this unbuilt project.

An inscription by one of Watkin's men notes the date when the project was begun,

except the word "begun" is hard to decipher.

Would it ever become clear?

Britain and, in particular, England, was not yet mentally prepared

for such a brutal incursion into her shores

that would put an end, once and for all,

to the splendid isolation of her natural fortress.

Britons instinctively believed

that the sea surrounding them guaranteed British security.

Anything that compromised this

threatened their cherished island independence and identity.

Perversely, fears of invasion

that had once scuppered the plans for a Channel Tunnel

would later prove to be the driving force

behind one of the most ambitious schemes of unbuilt Britain.

Hundreds of miles north of the White Cliffs of Dover,

it was proposed to cut an enormous battleship canal

through the heart of Scotland,

just to keep us British.

By the turn of the 20th century,

Britain had a new and dangerous rival.

Germany, under Kaiser Wilhelm II,

was intent on becoming a dominant imperial power,

but Britain had long ruled the waves

and wasn't about to give that up lightly.

To ensure the global supremacy of the Royal Navy,

the country embarked on a massive shipbuilding programme.

The first and last line of defence,

not just for Britain, but the Empire, is the Navy.

The question for English governments wasn't, "Do we need a Navy?"

It was, "Have we got enough Navy to do the job?"

Not to fight anybody, but to make sure

that nobody would even think about fighting the British.

At the time, the Navy was glamorous and its admirals celebrities.

The man driving the transformation of the Royal Navy was a bona fide star.

First Sea Lord, Admiral Sir Jackie Fisher.

Fisher's determination to win the naval arms race with Germany

would lead to another tale of unbuilt Britain.

This began in 1906

with a momentous development in the history of shipbuilding.

The launch of HMS Dreadnought.

HMS Dreadnought is a revolutionary vessel.

The world's first all big-gun, turbine-powered battleship.

It changed the technology of propulsion,

it changed the speed at which battleships moved

and it more than doubled their heavy gun armament.

It was a "raise you and double the stakes" motion

in a game of high-stakes poker.

Dreadnought changed shipbuilding technology for ever.

And the Admiralty felt sure

this huge battleship was the answer to keeping the peace.

But intelligence began to reach Britain

of a significant development across the North Sea.

The Germans had begun enlarging their Kiel Canal.

This was a huge waterway

which allowed their battleships

to pass between the Baltic

and the North Sea.

The very arena of a likely future war.

The Kiel Canal is of enormous strategic importance to Germany.

It allows them to concentrate their naval assets in one place,

in total secrecy, at will.

And there is an argument that we could benefit from something similar.

If the Germans were enlarging their canal,

it could mean only one thing.

They, too, had a ship on the scale of Dreadnought.

The British Navy could not be undermined.

Britain needed its very own Kiel Canal.

The idea of a British battleship canal was born.

This was a plan that would cut a huge trench

straight through the country.

A plan that would make Britain war-ready,

if it could be built in time.

That plan was known as the Mid-Scotland Ship Canal.

It was a proposal for a huge canal

on the scale of Suez or Panama,

the largest man-made waterways in the world.

The problem in Scotland was that many people wanted

to build it here, by the bonnie, bonnie banks of Loch Lomond.

Cutting right through the heart of Scotland,

it would have provided swift passage for enormous ships

sailing between the North Sea and the Atlantic.

The one obvious attraction of the Mid-Scotland Canal

was the link between the east coast and the west coast for strategic purposes.

The ability to move warships from one side of Britain to the other,

from the North Sea into the Atlantic,

without having to go up round the North of Scotland.

A canal on the scale of the one being proposed

would allow British battleships to avoid the navigation

of one of the most treacherous stretches of water

in the British Isles -

the Pentland Firth,

at Scotland's northern-most tip.

This canal would not just save time,

but countless lives.

It seemed just what Britain needed to defend her hallowed shores.

But the idea of building a massive shipping artery

through the stunning landscape wasn't new.

And profit, not defence, had been the motive.

In fact, the route had already been proposed

by a group of Scottish merchants

keen to expand trade with the Empire.

And it was to their blueprints that Naval attentions now turned.

At the time, two competing plans were drawn up.

One by the merchant traders of Glasgow,

and a second, rival plan by a group of Edinburgh businessmen.

The first, linked the River Clyde

and Glasgow to the Firth of Forth

and was known as the Direct Route.

The rival plan linked the sea lochs of the Clyde Estuary

to Loch Lomond and on to the east coast.

Accordingly, it was known

as the Loch Lomond Route.

I've come to the archives of the University of Glasgow

to look at the only surviving drawings based on proposals

for the Loch Lomond scheme.

It is incredibly detailed.

'I'm joined here by Professor George Fleming,

'an experienced civil engineer.'

From a civil engineering point of view,

how viable was the Loch Lomond scheme?

It was a massive cut from Grangemouth

through the Forth Valley, into Loch Lomond.

And that's the plan that we can see here, the Loch Lomond.

The plan you see is the line of the canal crossing the Forth Valley

and coming out into Loch Lomond.

And out from the top end of Loch Lomond, from Tarbet to Arrochar.

The proposed sea lane through Loch Lomond would have been enormous.

At 120 feet wide and 26 feet deep,

it was equal in size to one of the largest

and most difficult engineering projects ever undertaken -

the Panama Canal,

which took 23 years to complete.

The Loch Lomond scheme promised to be an equally complex undertaking.

In this section here,

the canal would be running through

but the landmass is much higher.

That would involve a cross-section cut shown here,

where you're cutting through up to 280 feet down into the base.

So you had a 280-feet sheer drop on either side of the canal.

And in other parts,

your cut would be about a 120 feet

through solid schist, mica-schist.

The unique mountainous landscape around Loch Lomond

would have proved enormously challenging to excavate.

Cutting hundreds of feet through solid rock

to carve a trench as deep as most tower blocks are high

is a dizzying thought

and would have wrought havoc for miles around.

This scheme represented a massive cut through the centre of Scotland.

Environmentally, not acceptable today.

Civil engineers essentially build things to service society.

And the more complicated a thing,

the more excited the civil engineer becomes.

And, at that time, environmental considerations didn't enter into it.

The evidence from the plans I've studied

enables modern 3D graphics

to show in dramatic detail

the impact of this colossal scheme

on the beautiful landscape around Loch Lomond.

Dreadnought sailing through a vast cut into the sea,

head to an enormous docking area at the south of the loch,

from here, they sail on to the Firth of Forth and the North Sea.

The initial price tag of the Loch Lomond scheme

was around £8 million,

the equivalent today of £2.7 billion.

But the arrival of the enormous Dreadnought

had an expensive knock-on effect for the canal

and all the other naval facilities.

Shipyards across Britain were already being overhauled

to accommodate her.

The ships get bigger and bigger.

That means the costs of building a canal go up and up and up,

because you have to make it bigger.

There was a cheaper alternative.

The Direct Route was almost 20 miles shorter than the Loch Lomond Route

which, on paper at least, meant it looked more affordable.

It was further argued that this route had much greater potential

to pay its way by earning commercial fees,

as it flowed directly into Glasgow,

then, the second city of Empire.

The financial viability of the proposed scheme had already been demonstrated by an earlier canal.

This is the Forth and Clyde Canal,

opened in 1790 for the same reason

that the ship canal was now desired -

to provide a shipping shortcut between the Firth of Clyde, on the west coast,

and the Firth of Forth, on the east.

I'm joined on the Forth and Clyde by historian Guthrie Hutton,

an authority on Scotland's canals.

Why was it that this canal couldn't be adapted to take larger shipping?

Er...main reason was the depth.

When it was first opened in 1790,

the vessels that would be using it were relatively small.

It would have been possible to widen it,

but not to deepen it.

That was the real difficulty.

The surveyors of the ship canal quickly ruled out the idea

of doing away with the smaller canal

and instead decided to build alongside the existing waterway.

The Direct Route would have been quite devastating.

The excavation for a Direct Route Canal

ran just, just beside this canal.

You can see the countryside there, where it would have gone.

It would have been an absolutely enormous chasm across the country.

Although the Direct Route was shorter than the Loch Lomond scheme,

it wasn't without its own costly problems.

The infrastructure of Central Scotland had kind of built up around the canal.

There were a lot of tunnels, for example, going under the canal,

railway tunnels, road, the aqueducts going over roads and so on,

very, very big structures,

which would all have had to have been taken down and rebuilt

in order to get the greater depth.

Amid claims that the simplicity of the Direct Route had been overstated,

a Royal Commission into Britain's canals was asked to examine both schemes.

It concluded that the cost of both routes had been underestimated,

having failed to take into account

at least 20 road and rail bridges needed to cross the canal.

Both routes now came with an estimated price tag

of more than £20 million,

or £6.7 billion in today's money.

But despite rising costs,

supporters of the project still insisted

that the canal was something the country had to invest in

to ensure national security.

Britain is now locked into a competitive race

for naval power with Germany and seeing who blinks first.

By 1909, the naval arms race had reached fever pitch.

And the public were demanding more money to be spent on defence.

The strategic case for the ship canal is made quite forcefully

and there is a point when Fisher likes the idea.

It would allow movement between the two coasts,

in total secrecy and absolutely safety,

and being able to use the shipyard facilities on the Clyde,

because you can get there freely.

As war with Germany grew ever closer,

the prospect of creating a backdoor to these great shipyards of the Clyde

made the canal more urgent in the eyes of some.

But Fisher was also pushing the government

to build eight more battleships.

The country was once again in the grip of a xenophobic terror.

A fearful public got behind him, coining the slogan,

"We want eight and we won't wait!"

Admiral Fisher used his connections with the press

to generate a naval armament scare in which he managed to argue

the Germans were close to the British in their numbers of battleships.

And the government eventually caved in

and they ordered eight battleships in one year.

This huge shipbuilding programme would cost the country

a staggering £16 million.

The case for a canal across the country,

through which these new vessels could sail,

appeared stronger than ever.

But this time, Fisher had gone too far.

His additional eight Dreadnoughts had effectively bankrupted the country.

Something had to give.

You can say, "Well, we can have a ship canal

"or we can have more Dreadnoughts...

"We'll have more Dreadnoughts, thank you."

The arms race, which had been the driving force behind the canal,

would prove to be its undoing.

You don't get the same agitation for the ship canal

as you do for building more ships.

You can't sail the ship canal round the world flying the flag.

It's a sort of invisible accretion of extra strength.

The Mid-Scotland Ship Canal had missed its moment.

It was simply deemed too expensive

at a time when the pull on resources was enormous.

Great engineering schemes are born of trying to solve great problems.

But in the face of war,

spending a couple of extra days getting from coast to coast

was deemed a relatively insignificant inconvenience.

Whereas Panama and Suez had shown that they would change the world,

the Mid-Scotland Ship Canal failed to convince those in power

that it was anything more than a shortcut.

Like many unbuilt plans,

the Mid-Scotland Ship Canal lingered on,

like a ghost of what might have been.

But, ultimately, the stars never aligned to allow it to go ahead.

Today, Loch Lomond thankfully remains free of warships.

The crowning glory of Scotland's first national park.

If war and the threat of invasion

had been behind the rise and fall of the canal,

perhaps even greater schemes might be possible

with the outbreak of peace.

But, as it transpired, it would take two world wars and seven decades

before Britain finally felt ready

to entertain a more physical relationship with the continent.

The Channel Tunnel was long a dream of its advocates,

the joke of its detractors.

Now the project is revived

as something much wanted.

Thoroughly practicable.

In this rocket age,

defence and security objections are much out of date.

In a new era of peace and co-operation across Europe,

the idea of a tunnel gained momentum.

And in 1974, there was one last thwarted attempt.

In an echo of the 1880 dig,

the tunnellers bored nearly a mile under the sea

before a change of government called the project to a halt.

But as European, economic and political integration gathered pace,

the case for a fixed link seemed irrefutable.

Even the naturally Euro-sceptic Prime Minister Margaret Thatcher

was eventually persuaded

and, in 1985, her government announced a competition

for a fixed link to Europe.

This sparked a clutch of grand designs,

including Eurotunnel's twin bore rail tunnel

and the incredibly ambitious EuroRoute,

a combined bridge and tunnel scheme.

For a time in the early part of the competition,

it did appear that...UK government,

Margaret Thatcher and the Cabinet, favoured the EuroRoute,

the part-bridge, part-tunnel solution.

Possibly because that gave full flexibility for car users

to simply drive onto the bridge and carry on into France hassle-free.

EuroRoute was the only scheme to offer the freedom

to drive straight to France.

Vehicles would cross a four-lane suspension bridge

to an artificial island,

recalling Thome de Gamond's early idea of building on the Varne Bank.

Here, shops and restaurants would cater

for the needs of cross-Channel motorists.

From the island, traffic would drive into a submerged tube tunnel,

linked to another island and bridge to France.

Running parallel to the road

would be a continental rail link.

In 1984, this gigantic, awe-inspiring vision was futuristic.

It almost seemed too bold.

But since then, other bridges have used the same techniques.

The famous Oresund Bridge, for example, between Denmark and Sweden,

is a hybrid bridge and tunnel

linking two countries by road and rail.

EuroRoute would have been three times longer.

It's a breathtaking thought.

And in the 1980s, when manufacturing was in steep decline,

this was just the type of major project

to get industry working again.

But it didn't happen.

EuroRoute probably failed

because it was almost double the price

of the, the rail tunnel option.

It gave more flexibility, it had some major backers behind it,

but ultimately it was the economics

that made it a riskier proposition all round.

In 1985, Margaret Thatcher announced the winner of the competition.

Eurotunnel got the gig.

EuroRoute and all the other plans became part of unbuilt history.

However, their legacy lives on in the tunnel we use today.

I've come to Folkestone to find out how the early unbuilt plans

helped to bring the tunnel to fruition.

Meeting me at the terminal

is Eurotunnel's Communications Director, John Keefe.

-Hello, John. Good to meet you.

-Lovely to meet you.

John, I've spent so long looking at plans for the tunnel

which never were realised.

But it's still something of a revelation to me

that you can get on a train and be in France in half an hour.

Absolutely. If we got on this one,

we would be on the platform, on the other side, in 30 minutes.

Eurotunnel is a rail shuttle service

using two running rail tunnels

and a third service tunnel, which is the one John's taking me into now.

John, this is tremendously exciting to be travelling through the tunnel.

That moment when the two shook hands through a hole in the rock,

that was actually at that point

the crossing between Britain and France,

a land crossing that hadn't been there since before the last Ice Age.

You know, that's how big it was.

Four years later,

the first passengers travelled under the Channel,

just as Mathieu-Favier, Thome de Gamond,

William Lowe and Edward Watkin

had envisaged more than a century before.

John's brought me to a point in the tunnel

where all the efforts of the past come together.

Well, this is where we have the crossover

of all of the different attempts to dig a Channel Tunnel.

If we go back to 1882,

we would have had tunnellers coming through from our left-hand side,

going right the way through here and heading out to sea.

In 1974, the tunnellers dug down from a shaft

and headed out to sea.

And you can see up here,

got "1974" on all of the segments along here.

So where we're standing is a sort of crossroads in history.

We've got 1882 going this way,

we've got 1974 all around us

and then, we've got 1986 going off into the distance

and eventually to France.

So this is absolutely the point

where those aborted projects of the past come together,

where the unbuilt and the built meet and join?

That's it. If we could go either side through these iron segments,

we would find the unbuilt Channel Tunnel.

Those early tunnel pioneers,

how close did they come to a practical solution for the tunnel?

They were bang on.

I think all of the engineers who had anything to do

with previous attempts to build a Channel Tunnel would be fascinated to come down here,

and I think they'd be very proud to know

that parts of their thinking is here, right here, right now,

inside the modern realisation that they dreamt of so many years ago.

There's no doubt that the Channel Tunnel

is one of the wonders of the modern world.

It's a marvel of engineering,

carrying thousands of passengers for 31 miles under the sea every day.

It's also a perfect example

of how attitudes to our continental neighbours

have helped write the history of our greatest engineering projects.

The political and economic climate was finally right

for the Channel Tunnel project to go ahead in the late 1980s.

The Mid-Scotland Ship Canal, by contrast,

never quite gained sufficient momentum

to convince the governments of the times.

To this day, it remains just one of a wealth of ideas

that make up the world of unbuilt Britain.

Join me on my next investigation

when I'll discover how the Great Fire of London

inspired the most beautiful unbuilt city in Britain,

and how the city of Glasgow was nearly demolished

by a visionary with a grand plan.

Subtitles by Red Bee Media Ltd