(mellow music) (Big Ben chiming) ♪ (Dr. Keay) Big Ben... ♪ ...the heartbeat of the nation.

Since 2017, it's been undergoing the biggest restoration in its history.

Oh, my goodness, look at that!

We have exclusive access behind the scaffolding...

It's the most enormous space in here.

I had no idea that it was quite so huge.

(Clare) Yes.

(Dr. Keay) ...to uncover hidden problems in the clock... (Huw) That's just one of the small parts which could stop the clock.

(Dr. Keay) ...and reveal the country's best craftspeople stretch their skills to the limit...

It's bespoke on a whole new level, really, isn't it?

...all to save a British icon.

Are their any replacement bits in here?

-No.

-No, how amazing.

Now, after four years of unprecedented challenges...

So, would you say that this is one of the elements on the building that's needed -more extensive work?

-Yes.

(Dr. Keay) ...it's finally time to witness the rebirth of one of the most famous buildings in the world.

-This is just a brief preview... -This is a preview.

...of what it's gonna be like.

Oh, isn't it extraordinary?

(exciting music) ♪ (thunder rumbling) My job revolves around historic buildings, and I've been lucky enough to work on some of Britain's greatest landmarks.

But for me, there is one structure that never fails to make my heart skip a beat.

So there it is, Big Ben, still encased in an absolute mountain of scaffolding.

And behind all of that, the work of this incredible team of craftspeople goes on.

The whole thing on an absolutely breathtaking scale.

(bright music) Since 2017, the Elizabeth Tower, as it's officially named, has been unrecognizable.

Three of the great clock faces, each one larger than a double-decker bus, became empty shells, with all eight of its giant hands removed... Ooh, look at that.

...and sent off-site for repair.

The roof, with its gilded spire and ornate cross and orb, was dismantled.

♪ A little naked, doesn't it?

-It is.

-It's all come off.

Seven hundred elements of damaged stonework were replaced with Cadeby limestone, each new piece hand-carved by masons working from a yard at the bottom of Big Ben.

(tapping) The massive clock mechanism, which has been ticking almost continuously for over a century and a half, was stopped.

♪ For all the craftsmen and craftswomen who are working on this project, it really is the project of a lifetime.

And right across Britain, in all their studios and workshops, is a great team of people working together on a really remarkable shared endeavor, which is to make Big Ben look once again like it did on the day that it was completed.

(gears clanking) (clock chiming) For the first time since the clock tower was built in 1859, the very heart of Big Ben has been removed and transported to a workshop outside London.

(birds chirping) (playful music) For the next two years, clockmakers Ian and Huw, with a specialist team, will strip back, inspect, and repair every part of its mechanism.

It's an enormous job which starts with unpacking all five tons of clockwork.

And if anything is missing, they only have themselves to blame.

(Ian) As they were coming out of the tower, we labeled everything.

And we've cut down the number of people who have actually touched it.

So, it really, if we've lost anything, it's us.

There's a little bit of pressure.

There's a lot of pressure.

But--but the honor of being able to work on the greatest clock in the world is just incredible.

I don't think people realize how much equipment it takes just to ring Big Ben and the quarter bells.

This is Victorian engineering gone mad, basically.

We've got 11 and a half tons of clock to ring a 13-ton bell, nearly, and the four quarter bells.

I think people like it because it is still purely mechanical.

People could put a big electric motor up there to do the same job, but it wouldn't be the same, would it?

(gears clinking) (Dr. Keay) The clock is run entirely by gravity.

Three weights hang below the mechanism, moving up and down a shaft in the center of the tower.

As the weights drop, they provide the power to drive the clock and ring the bell of Big Ben and its four quarter bells.

(bells ringing) (gears clinking) (Ian) That needs to go back towards you.

-Go towards me, yeah?

-Yeah.

(Dr. Keay) A key part of restoring the mechanism is to reassemble all the elements and ensure that they fit perfectly in place.

At the moment, we're working on the hammers, another huge part of the clock, you know.

Yeah, it's all right just driving all the faces, but everybody knows the sound of the Great Bell and its four quarter chimes playing the Westminster Chimes.

(Dr. Keay) Ian Westworth and Huw Smith are Parliament's clockmakers, who look after all of its 2,000 clocks.

♪ For them, taking apart a mechanism is usually a delicate process, requiring precision skills, tiny tools, and a steady hand.

(hammering) ♪ Now, their job also requires brute strength.

(Ian) Well, what we're trying to do is fit the hammers back onto the arms.

We take it apart, clean it, reassemble it, just to make sure that everything we know is gonna go back together properly.

And that's just what we're tryin' to do now.

(metal rattling) As you can see, it's... trial and error trying to get it into the right place.

(Huw) Try to shuffle it in.

(Ian) And I think we found that this hammer should be at that end.

That's why the arms don't go.

So, can we pause and swap the hammers around?

So, come on, hammer.

I would like to say another word, but there are ladies present.

(laughing) (Dr. Keay) Ian demonstrates just how heavy a 90-kilo hammer is.

(Ian) So, this is one of the hammers off the fourth quarter bell.

This is the one where we've got two hammer heads, one here, one just beside me.

And what we're having a look at while we're got them apart is the face of the hammer is actually wearing away 'cause it's constantly bashing on the bell itself.

So what we're looking at is either reprofiling this hammer, give it a nice dome again, or what we're lookin' at is turn the hammer around and go to a new face, which they happened to have cast on for us 160 years ago.

So there's pros and cons for both of it.

If you reprofile this, you don't have to take everything else apart, but the hammer then becomes slightly lighter.

If it becomes slightly lighter, it'll actually give it a different tone when it hits in the bell.

So, do we take more off or just use the fresh end?

(Dr. Keay) What would you want to do?

(chuckling) Good question.

-Still up for debate.

-Still up for debate, this one.

(Dr. Keay) Back at Big Ben, another iconic part of the building will soon be removed, the Ayrton Light.

This is a giant lantern, which sits above the belfry near the top of the tower.

Before it's dismantled, Parliament's principal architect, Adam Watrobski, took me to find out how it had coped with over a century of exposure to the British weather.

-Oh, golly, look at this!

-Well, we're now, -this is-- -You're on top of the world -up here.

-The top of the world.

This is 393 steps above where we started from.

And in the middle, you've got the Ayrton Light, which is, essentially, lighthouse technology on top of the clock tower.

And this shines whenever either hou-- at night, whenever either house is sitting.

(Dr. Keay) Yes, and you sometimes see this if you're walking through... -That's right!

-...Parliament Square at night, -the light's on, don't you?

-That means that at least one of the houses, or both the houses are sitting.

And you can see there are modern lights in there at the moment, but originally, this had 68 gas jets in it.

-Right.

-Because, originally, it just faced Buckingham Palace, it faced westwards.

(Dr. Keay) The Ayrton Light was fitted in 1885 to signal when the House of Commons was sitting after dark, and to help illuminate the dark streets of Westminster.

It was one of the brightest lights on the London skyline, allowing Queen Victoria to see it from her home in Buckingham Palace.

This led MPs to joke that Victoria was using the Ayrton Light to keep an eye on how late they were working.

It sort of literally is a beacon of Parliamentary -democracy, isn't it?

-It is, it is.

(Dr. Keay) Because actually, it shines when-- (Adam) It shines when democracy -is in progress.

-When democracy is... -Yes, yes.

-...happening.

Sadly, our beacon of democracy is showing its age.

You can see there, can't you?

-That's really... -You can see quite clearly here.

-So, we're going to look at... -...flaking away.

(Adam) ...see how much of this we can take apart, but it's not always so easy, as you can see.

Steel, so of course, it's beginning to rust much-- much worse than you would expect on ironwork, and there's a lot of rust behind here, which is beginning to build up and to push this component forwards.

I can feel layers of rust underneath there.

Then there's-- This is a timber frame, which is inserted, which is suffering rather badly.

We'll probably need to renew that bit, but certainly this can be rescued.

(Dr. Keay) Yeah.

The framework will be dismantled and sent up to Yorkshire for repair.

The task of replacing all the glass falls closer to home, in a studio in East London with stained glass artist John Reyntiens.

(blade scoring) (glass snaps) John has worked on major projects, from Windsor Castle to Westminster Hall.

He's made his name with delicate pieces of glass.

(glass snaps) Cutting great sheets for the Ayrton Light is such a new challenge for John, he's asked a friend to film it.

(John) Everyone in business, I said, "How do you cut 8.8 laminate when they're in big sheets?"

They never quite-- they just said, "No, I wouldn't go near it.

Don't do it, get someone else to cut 'em."

So I spent the entire week wondering how we were gonna do it.

(Dr. Keay) The glass is almost one centimeter thick and weighs 90 kilos.

John doesn't have a table large enough to cut it, so it's time to get inventive... (John) Keep going, keep going.

(Dr. Keay) ...by scoring and cracking the glass against an old door frame.

(blade scoring) ♪ (John) That's the awkward bit.

(anxious music) Okay.

Here we go.

Right, okay.

So, you're gonna walk it 'round the other side.

Just to crack--yup.

-Has it gone?

-Can't we hear it?

(John) You should hear it.

Keep going, keep going.

Keep going.

♪ Keep going.

(blade scoring) Keep going, keep going.

(indistinct speaking) ♪ And that's how you cut an over-long piece of lami-glass without a tilt table.

Little bit primitive, but it does work.

Now it's our tea break, so we're gonna leave Wendy there on her own.

♪ (mellow music) ♪ (Dr. Keay) I've been following the renovation of Big Ben since it started in 2017.

It's an ambitious project on a mammoth scale.

The aim is to return the clock tower to its original Gothic appearance, with the addition of a few modern features, such as a brand new lift.

♪ The lift will be fitted in a disused ventilation shaft running from the top to the bottom of the tower, and the engineer is Clare Hartley-Marjoram.

It's the most enormous space in here!

I had no idea that this, this, you know, ventilation shaft was quite so huge.

Yeah, so now obviously, finally, we've opened it up on nine floors and built the scaffold.

We got full access, and we can kind of start to set everything out and make sure it fits.

(Dr. Keay) How many, kind of, stories up are we -here of scaffolding?

-So, this is at about number 30, so we've got about four more levels to go to finish it off.

So we're about 60 meters up now.

(Dr. Keay) Okay, so if we peered down this hole here?

Oh, my--yeah, okay, that's slightly... (Clare) I did have vertigo before I started the job, and it's cured, so, yeah.

(Dr. Keay) So you started this job being in charge of all this work on Big Ben -as a person with vertigo?

-I did, yeah.

I didn't tell my boss that, but, yeah, it lasted the first few-- it literally took a week, and then I'm--I'm fine.

(Dr. Keay) You're a brave lady, oh.

So this is a ventilation shaft, as originally built.

What was it ventilating?

I mean, what was it that was going up here?

-Just the air?

-Well, so, the time when the tower was built, the buildup of sewage and waste was really bad around London and in the Thames and everything, so the buildup of sewage gasses were actually diverted up and out of this shaft.

(Dr. Keay) This shaft was part of an early example of air conditioning built throughout Parliament to combat the stench rising from the River Thames.

In the mid-1800s, London had no sewage system, and human waste was poured directly into the river.

This led to outbreaks of cholera and the great stink of 1858, when the Thames became so foul, many Londoners refused to leave their homes.

The ventilation system was built to combat the stench.

A fire drew fresh air down the tower and into Parliament.

Eventually, the shaft became obsolete and was bricked up, leaving a space for the new lift to be fitted.

Looking up here, you can see the hole in the wall where the shaft of the clock mechanism goes out to, presumably, the clock face on that side.

(Clare) Exactly, so the-- all three spindles for the normal clock faces are in that room, but this fourth one, which obviously the shaft is in the way.

The original spindle came through here, and then a box was here, which was actually called the coffin box, it was the only way to access that spindle.

And it was basically a copper box kind of hanging in the middle of this, -this shaft.

-How terrifying.

So somebody, some poor 19th century clock mechanic would have to come out of that little door onto this terrifying little kind of bridge over the abyss -to, you know, oil the spindle?

-Yeah, exactly.

So now, we've obviously got these platforms in, it'll be much better access for them.

(Dr. Keay) Yeah.

Outside the lift shaft, 76 meters high, sits the Ayrton Light, one of the most damaged parts of the tower.

(lively music) ♪ Now it's being completely dismantled and its frame sent off for repair.

I'm curious to find out how much of it can be restored.

So I'm heading up to Shepley Engineers in Yorkshire.

Here, head of restoration Trevor Marrs is responsible for over 3,000 elements of metalwork on the clock tower.

♪ Each one of these elements will be stripped down, inspected for damage, sprayed with a protective zinc coat, and then repainted.

(Trevor) So, this is the-- this is the Ayrton Light.

(Dr. Keay) Okay, so the light itself, which is sort of in the upper part of the clock tower, sits above this, doesn't it?

-It does, yeah.

-So, what's happening here?

(Trevor) Well, due to its exposed position, it was in an open part of the structure, it's received an awful battering over the years.

So what you see here is probably the bulk of what's actually survived.

(Dr. Keay) Okay, so the sort of panels that close up these openings and elements of the upper part are being, -are having to be remade?

-Yes, they're having to be remade.

So, a lot of the structural elements that, as you can see from here, a lot of these, we haven't been-- we haven't been able to save, so.

(Dr. Keay) So this shows you what it is-- the whole thing is like.

So we've got this bit, we're looking at this bit here.

Quite a lot of all of this is having to be completely remade.

-Yes.

-Wow.

Sadly, Trevor is forced to replace almost 80 percent of the frame.

So what--what will you be doing, then, next with this?

Presumably, instating the new elements -back into the spaces?

-Yeah, yeah, so what we'll do is we'll start producing the cladding panels, which will need to be, again, as with everything on the tower, will have to be unique.

We'll then start constructing the upper elements of the, what we refer to as the lantern.

(Dr. Keay) Yup, so the actual light that's in there, isn't it?

And then there's sort of glazed panels that -it shines out of.

-Yeah, yeah.

(Dr. Keay) So, would you say that this is one of the elements on the building that's needed more extensive work?

One of the more, sort of, needy parts of the building -in repair terms?

-Yes, yes.

Once we actually got access into the tower, we could see that this was one of the elements that would take a significant amount of work.

(torch roaring) (calm music) (Dr. Keay) With so much of Big Ben now dismantled in workshops across the country, it's down to Parliament's principal architect, Adam, to ensure it all remains true to the original design.

Today, Adam is taking me 60 meters up onto the scaffolding to show me the most-photographed part of Big Ben, the clock face.

Ah-ha!

-You can see quite clearly... -Yes!

(Adam) ...this has been primed, of course, and repaired, but this is the cast iron frame.

(Dr. Keay) We're at the six here, aren't we?

-The bottom of the dial.

-Yes, we're right at the bottom of the dial here.

(Dr. Keay) And it's naked, it's had all its -old paint taken off.

-It's had everything taken off, and it's had its new undercoat on, and it now needs to be top-coated, two top coats, of course, in the blue, but it needs to be glazed.

(Dr. Keay) Reglazing this clock face is no easy task.

(Adam) These amazingly thin glazing bars, if you can see, there's practically no purchase there for the glass at all.

So the glass cutting has to be extremely accurate in order for to fit into that.

Each and every piece, of course, it has to be templated 'cause they're all a different size, as you might imagine.

But quite an extraordinary job to glaze, actually.

(Dr. Keay) This extraordinary job also lies with stained glass artist John.

For the last year, he has been hand-cutting mouth-blown, pot opal glass for the four great clock faces.

(John) We got about four or five mil.

to play around with.

Let's see if I can snap it.

Oh, yeah!

A-1.

(Dr. Keay) Today, John and his team are painstakingly fitting the freshly cut pieces into the north clock face.

(anxious music) Okay, push it, pushing out.

(Dr. Keay) John, it's really interesting sitting here because, of course, it reminds you that the glass is offered up behind the clock face, isn't it?

So, it isn't necessarily obvious if you don't know that each individual element here is a separate piece of glass rather than big, flat plates of glass being applied over the ribs from behind.

(John) Yeah, and people do think it's great big pieces of glass, and I have to explain, "No, it's not, it's smaller sections."

(Dr. Keay) Each one of these--I mean, that piece couldn't go in there, and that piece couldn't go in there.

Each piece is specific to its-- (John) Every piece had to be templated individually.

So, and actually, if you look at the templates, every template is a different size.

So there's not-- you couldn't suddenly use five of those in one place.

You have to template everything.

(Dr. Keay) It's bespoke on a whole new level, really, isn't it?

(John) Yeah, and what's nice now, if a piece gets broken, we got a template for it.

(Dr. Keay) For Big Ben trivia lovers, it's a well-known fact that there are 312 pieces of glass in each clock face, or so they thought.

Remind me how many-- how many pieces is it that you've got -in these clock faces.

-We've got 324.

There was 312, but we discovered another 12 pieces, which aren't-- they're actually down where the clock arms come out, -and there's plate-- -Oh, under the middle, -the sort of disc, where the-- -So there's 12 triangles that were--actually caused a great deal of concern, and I had people ring me up, "Are you sure?

I thought--in the guidebook, it says 312."

And I said, "I'm afraid the guidebook is incorrect."

-It's 324.

-Well, you should know.

-Yeah.

-And that's per clock face, -isn't it, so that's times four.

-Yeah, yeah, yeah.

(John) So that is 1,296.

-Wow, that's a lot of glass.

-Yeah.

Do you feel like you can't wait to see the back of it?

Or, do you feel sad at the thought that this is the last face?

(John) No, I'm really sad, and it's such an important heritage site project that, actually, I'll be really sad to close this one out, and that's it.

It'll be-- yeah, I won't like that bit.

-No.

-No.

(quirky music) (Dr. Keay) As part of the most ambitious makeover in the history of the tower, the north clock face will soon go through a radical transformation.

♪ (bright music) ♪ (man) Okay, so I'm gonna take one picture like this, then I'm gonna get everyone to come closer to us.

(Dr. Keay) It's two and a half years into the project now, and today, 120 of the workers have been called to the bottom of the clock tower.

It's time for the official team photo of Project Big Ben.

(man) All right, everybody ready?

Woo-hoo!

(Dr. Keay) So, Abbi, what is your role on the project?

(Abbi) Well, I'm the head of finance, and I provide financial advice and support to my colleagues on the project board.

I'm involved in all the projects, but for this one in particular, the whole team, right from the ground to the board, seems to gel very well.

I think it's once-in-a-lifetime thing, but also it's our heritage in Britain, and I think it's one precious thing that I'm very glad and pleased to be a part of.

(Dr. Keay) Oh, hear, hear to that.

(man) Okay, then we're gonna get everyone to come closer, please.

Everyone to, like, march up.

All the way in, all the way in, all the way in.

♪ (Dr. Keay) The thrill of working on such a famous building is tempered by the fact that every decision is scrutinized across the globe.

(indistinct speaking) (Matthew) The stats about who knew we were doing this were astonishing, like 90 percent of the UK population knew what we were doing.

I was abroad in a very obscure mountain valley in Europe, and I opened my German-language local newspaper, and that ran a story on it.

(man) Okay, that's, and just in slightly this--yup, brilliant.

(camera's shutter snaps) The silence, oh, my God!

(crowd laughing) I want everyone to go, "Bong!"

(Dr. Keay) So what sort of things have you enjoyed, or have been kind of memorable about things that have come out during the project?

So, I think one of the most memorable things was silencing the bells.

We really didn't expect the sheer public interest in it.

(Dr. Keay) But presumably, that's also a reflection of the building mattering to people.

(Charlotte) Well, and that's where the responsibility comes in.

It's not just our building, it's the nation's building, it's the world's building that we are looking after.

-Yeah.

-Lovely, thank you very much!

(Dr. Keay) Saving Big Ben is a team effort on a national scale.

All across the country, craftspeople are using their skills on different parts of the tower.

-Hi, you two!

-Hi, Anna!

(Dr. Keay) Crickey, well, things have moved on a bit here, haven't they?

(Ian) They certainly have.

(Dr. Keay) For Ian, Huw, and the clock team, that means inspecting every cog, wheel, and screw of the mechanism.

Huw, I mean, this looks like it's sort of it's all finished, I mean, it's looking absolutely beautiful, all these elements here, but I know that it isn't.

So, what stage are we at?

(Huw) The stage that we're at at the moment is that we've actually now cleaned all the parts.

We put a primer on to protect the surface of the metal.

(Dr. Keay) So that's the red color we see on here?

(Huw) Yeah, so this isn't the finished color.

(Dr. Keay) Which element are we looking at here of the clock itself?

(Huw) This is the north dial motion work.

This is what actually drives the minute hand and the hour hand on the north dial.

(Dr. Keay) So this is the shaft, which, as it were, transfers the motion of the descending weights... -That's it.

-...through to these, which turn the actual hands.

(Huw) Yeah, to work out, actually, what is bein' worn, et cetera, we'll actually get this actually turnin'.

-Turn the counterweights.

-Oh, yes, I see.

Okay, so that's your, sort of--, you're mimicking, as it were, -the motion of the clock drive.

-The clock drive.

(Ian) And you can actually hear -very quietly.

-Quite a lot of this is actually listening to it.

-Yeah.

-Oh, yes, yeah, yeah.

(parts moving) (Dr. Keay) It's a wonderful sound, isn't it, hearing it -going 'round?

-It's nice when it's nice and quiet.

If there's clunks... (Dr. Keay) That's when you wanna worry.

(Huw) ...you know there's something.

God forbid if there's any grindin'.

(Dr. Keay) That's what you really don't want.

(Ian) Yeah, grinding's no good.

(Dr. Keay) And these are all the, the sort of 1850s bits, are they, 'cause they look so sharp!

Are there any replacement bits in here?

-No, not to my knowledge.

-No.

How amazing.

(enchanting music) Before being reassembled, every part has to be deep-cleaned in pressurized water.

It's only when 161 years of dirt is washed away that potential problems come to light.

(door opening) (Huw) This is another piece, but a little bit of dirt or grease have actually got into this here.

If I-- (rigid scraping) Yeah.

Where... (smooth scraping) ...that's the difference.

So.

(Dr. Keay) Trapped dirt has worn down the spindle's surface.

If left untreated, it could have had catastrophic consequences.

(Huw) That's just one of the small parts which could stop the clock.

We couldn't know about this because this is one of the parts that we can't get to with easy access.

So this is one of the important reasons why we have checked every single part.

(Dr. Keay) Next to the workshop is a temperature-controlled room where the most important part of the mechanism is also running.

This is the triple-legged gravity escapement.

It allows the clock to use gravity, not mechanical force, to power the pendulum.

Ah-ha!

Here--well, this is amazing.

It's like seeing a bit of-- a bit of a person you know on a sort of life support machine, isn't it?

'Cause there's no sort of one element here... -Yeah, so this is... -...running (Ian) ...just part of the going train.

So this is the bit that we're testing at the moment up here.

(Dr. Keay) So now you've got the pendulum hanging -right down there.

-We've got the pendulum hanging down, and we've got a very small weight just to let it all run through the system.

(Dr. Keay) 'Cause this is really the sort of absolute heart of the matter of this clock.

(Ian) This is the ticking heart of the clock.

Without this bit, everything else doesn't work.

-So this has to be perfect.

-Has to be absolutely perfect.

(Ian) So that's why we've already got it up and running.

This needs to be looked at, restored, and repaired, and then left on test so it actually beds itself in.

So when it goes back into the tower, it'll be as close to perfect as we can get it.

It'll need some time in the tower.

We'll get it, again, set up in the tower as early as possible so it's ticking away in the environment that it's gonna live in for the rest of its life.

(Dr. Keay) The clockmakers are part of a 500-strong team of specialists involved in restoring Big Ben.

Each one is using their unique skills to reach a shared goal, to make the tower look exactly as it did when first built, right down to the colors on its clock face.

Conservators have stripped back a century and a half's worth of paint and sent it to labs for state-of-the-art analysis.

Their aim: to discover the original color scheme.

Oh, my goodness, that's completely extraordinary.

It's blue, it's not black at all.

Now, gilders and painters are returning the clock face to a vibrant palette of blues, red, and gold.

These exuberant colors are in stark contrast to the somber black we're accustomed to seeing.

I'm curious to find out what caused this dramatic change.

(dramatic music) Hi, Mark, how are you?

-Nice to see you.

-Hello, how are you?

(Dr. Keay) Yeah, yeah... Mark Collins is historian of the Parliamentary estate.

He's been investigating when Big Ben morphed from multi-colored to monochrome.

(Mark) Fortunately, the original drawing by Charles Barry, the architect of the Palace of Westminster, -has survived.

-Oh, really?

So his drawing of what he intended it to look like -exists?

-It still exists.

-Oh, brilliant!

-I brought a copy.

And you can see that the black -is nowhere to be seen.

-Yes!

(Mark) There's a little bit more gold, but the most outstanding part is, of course, the dials have colored in blue.

-A lot fresher... -Yes!

(Mark) ...and I think there's almost a festive atmosphere to it, really, because you've got these red shields of St. George crosses along the top there, you've got six along the top.

(Dr. Keay) See, there isn't actually a single inch of black on this, is there?

(Mark) No, that's right.

People think that the Victorians used black a great deal because we see railings, Victorian railings and buildings painted in that color.

But it's only in fact in the 20th century that you really find black being used.

They were very colorful, in fact, the buildings in those days.

(Dr. Keay) It wasn't until the Depression of the 1930s that Big Ben started to look more drab.

And do you think it was part of a-- I mean, do you think it was a deliberate thing to sort of-- sort of make it more sober, -more serious looking?

-I think it probably was.

(Dr. Keay) It was a pretty serious time, wasn't it?

(Mark) Very difficult time, just before the Second World War, and very often here called the "sad thirties," -in fact.

-Yes.

(Mark) And so, they--they were also thinking, I think, of the atmosphere of London, which was particularly filthy at that time with smoke and smog.

And they just wanted to cover it in-- -Yes, 'cause I suppose... -Tidy it up.

...I suppose at that time, the stonework had itself gone--I mean, like lots of London-- had gone very black.

(Mark) It had, that's right.

So in fact, surrounding this, the stone wouldn't have looked as bright as it does on this drawing, or on the building as we will see it when the scaffolding comes down.

(mellow music) ♪ (Dr. Keay) It took 12 months to put up 800 tons of scaffolding around Big Ben.

♪ When it reached 96 meters, one of the world's most exciting restoration projects began.

The top of the tower was stripped of its 3,500 cast iron tiles.

All that was left was the original frame.

Three years later, the roof is the first part of the clock tower to be restored, and the end of the project finally feels in sight.

Parliament's principal architect, Adam, takes me up to level 37.

Oh, my goodness, look at that!

(Adam) This is the first bit to be completed.

(Dr. Keay) It's like a rebirth, isn't it?

-Look at it!

-Isn't it astounding?

-It is absolutely gobsmacking!

-If you start right at the top with the spray of flowers, of course, and the gilding, and the cross, it's just amazing, and the crown.

(Dr. Keay) Ah!

(captivating music) ♪ (Adam) This is the Ayrton Light level, and in order to get the Ayrton Light in, we've had to take out the scaffolding from inside.

-So this is just a brief-- -This is a brief glimpse.

This is a brief preview.

This is a brief preview of what it will be like.

♪ -Oh, isn't it extraordinary?

-It's extraordinary, isn't it?

♪ (Dr. Keay) Yes, now look at the light, the gold and the gray, and then all these brilliant... (Adam) And it's been very beautifully done.

It's been very beautifully done.

♪ (Dr. Keay) But it's also so wonderful having, having seen various of these individual elements, like those little-- detail over the dormer windows, taken completely to pieces, absolutely disassembled, and then all being put back magically together now.

♪ Adam, how does it feel for you, who's been on this project?

-Well, I-- -Make your heart leap a bit?

Yes, I saw the roof revealed.

I haven't actually seen this bit until now.

This is the first time I've seen this bit because the scaffolding's been taken down.

First time I've been up at this level.

It is profoundly romantic, isn't it?

I mean, the whole thing really just looks like a fairy tale when you're standing here.

There's something wonderful about the fact that, in a way, this building that's so serious in that it represents statehood and democracy, and all that kind of stuff, actually, when you look at it closely, it feels--has this wonderful, sort of heart-lifting, magical quality to it that's actually not at all what you imagined.

♪ It's completely spellbinding seeing the top of Big Ben today, because as the scaffolding has been coming down, it gives the impression that the building is rising up.

And it looks like the Birth of Venus or something, this amazingly beautiful, pristine, rather unfamiliar building seeming to rise up out of this great pile of scaffolding.

And it really is breathtaking, and it reminds you of the aspirations that the Victorian architects had for this building.

I love this stage in the process when things start clicking into place.

Hearing the clock's familiar tick again, and seeing the newly gilded spire gleam, it's starting to feel as though the end is in sight.

Then, suddenly, work is brought to a shuddering halt.

(bright music) ♪ (flag whipping) (Boris Johnson) Good evening.

The coronavirus is the biggest threat this country has faced for decades, and this country is not alone.

All over the world, we're seeing the devastating... (Dr. Keay) The United Kingdom goes into lockdown.

Work at Big Ben grinds to a halt for more than three months.

These are testing times for the team.

Before the pandemic, the original budget had already increased from £61 million to £79 million.

And now that constructors have returned to work, they are having to socially distance in a clock tower with a tiny footprint of only 12 meters square.

So, Nick, we're standing about 200 feet up in the air, aren't we, on this scaffolding that's on the outside -of Big Ben?

-We are, yes, yeah.

(Dr. Keay) And it's a real reminder of just how challenging it must be for you and the gang here to operate a site with social distancing in the middle of a pandemic.

-It's very--it's very difficult.

-I just wonder -what that's been like.

-Yeah, I mean, it's been very difficult, as you can see, this sort of outer scaffold's probably about two and a half meters, and therefore, to maintain two meters' social distancing as we require, it's been a big challenge.

(Dr. Keay) And also, even just getting, I mean, to get people up here, they've all got to come up in the lift, and that presumably all has -new arrangements -So it's three at a time in the lift or in the hoist.

It's what we have to do.

You know, we can't obviously cram people into a confined space, like a passenger hoist.

What would you say the impact of the COVID pandemic on this project will be?

(Nick) We were shut down for 15 weeks, so that's obviously had a-- had an impact straight away.

So for 15 weeks, we weren't doin' any physical work on the site, so you can imagine if the site shuts for 15 weeks, then that just all-- everything just shifts over by the equivalent amount.

But then, going forward, we've obviously-- when we brought guys back to the job, guys and ladies, back to the job, we've had to come back very, very slowly.

So we started with about 14 operatives, and then we've tried to raise that.

But we've done it very, very slowly and incrementally, just to make sure we can manage it safely, because the last thing we want is for somebody on the estate or somebody within this job to go down with COVID, and then have to, obviously, take the time off.

And there's obviously huge potential for it to spread if we don't manage it properly.

(Dr. Keay) So, in the four months or so since the site reopened, what are the big things that have happened here?

We've got a chance now to strike the scaffold at the top of the tower, which is another amazing milestone.

And we're taking down the scaffold from the top roof, past the Ayrton Light, past roof A, which is the bigger of the two pitched roofs.

We're takin' it down to the belfry level, which is, obviously, where Big Ben is.

So, it's gonna be quite a site, and I'm really lookin' forward to seein' that myself, so.

(tranquil music) (Dr. Keay) Despite all the setbacks, Nick and his team have just reached another significant milestone.

♪ -Here we go!

-Ha-ha!

Here it is, the Ayrton Light in all its glory!

Back in its-- back in its home spot.

(Nick) Yup, back where it belongs.

(Dr. Keay) Gosh, it must be quite a moment for you, Nick, -seeing it.

-It is, it is.

(Dr. Keay) Seeing it go on this incredible journey, and then be bit of the puzzle being put back together.

(Nick) It is like a jigsaw puzzle, actually, isn't it?

It's 163 pieces that have all been taken apart.

-Is that how many pieces-- -163, yeah, you wouldn't think it, but very small pieces that are all taken apart, taken back to Shepley's, and then brought back to site and installed in its true location, where it's meant to be.

So, yeah, it's a really, really amazing thing to come up here and see it back.

(Dr. Keay) Well, I think it's a huge credit to all of you.

-Wonderful.

-Brilliant.

(upbeat music) ♪ (Dr. Keay) Although the clock tower is still a building site, nothing will stop Big Ben ringing out for special events, such as Remembrance Sunday.

There's only a week to go before the big day, and Ian, the clockmaker, is back to prepare.

But with no mechanism, he has a temporary solution.

'Cause we don't have the clock here, we can't ring the bell, but this is a very important day, being Remembrance Sunday.

So this unit here is strong enough to actually go 'round and pull the hammer off the bell and ring it as if we had the clock here.

(Dr. Keay) This electric motor will pull the 200-kilo hammer that strikes Big Ben.

(Ian) We have a programmable system in this box here, and what it does, it sends a signal to a big electric motor, and it raises and releases the hammer to create the bongs on Big Ben.

So what we do, we actually have to get this motor running before 11:00 so the hammer is lifted, and exactly on 11:00, it strikes the bell.

I'm gonna slowly test the system.

I will slowly wind the tension on so the motor will be able to lift the hammer very slowly and very gently first off.

And then the lift, the amount of lift, which is how far the hammer will go before it's released, will get bigger and bigger until the bell's sounding like it does when the clock rings.

(bell bonging) (Dr. Keay) This is the first time in ten months that the bell has rung out.

Big Ben strikin' out on the quarters chiming, I've really missed.

So it's since been very quiet for a very long time, and I've missed that.

So actually, to actually go out and make some noise.

I like making noise.

So we actually-- and it doesn't come much louder than this.

Okay, Johnny.

(bell ringing) That's good, thank you.

This year is going to be extra special.

(officer shouting commands) The great clock and Big Ben itself hasn't rung out at all this year since New Year's Eve.

And we're gonna make a special effort just to make sure that everybody still has something to think about, other than just what's going on in this terrible time.

(Big Ben ringing) (birds chirping) (Big Ben continues ringing) (Dr. Keay) There's still a long way to go in the restoration before we will fully see Big Ben again.

Work is due to continue until 2022.

But already, we've had tantalizing glimpses of what it will be.

And it's finally time for its iconic north clock face to be revealed to the world.

(suspenseful music) This is the original color scheme.

♪ Out: the brooding black on the dials!

And in: a rich Prussian blue.

♪ Out: the gloomy corners, and in: gleaming gilded stone and bright cobalt blue.

Out: the patchy post-war glass, and in: mouth-blown, hand-cut replacements, each piece bespoke.

Out: every inch of black paint, and in: vibrant reds, greens, and purples on the national shields.

Welcome to Big Ben's stunning new clock face.

I like to imagine that if Big Ben's architect, Charles Barry, were to look upon the work being done today, he would greatly approve.

(dramatic music) It's been really heartening being here today, and actually seeing how much has been achieved, and how the whole team have found ways of carrying on this amazing work has been completely brilliant.

And to have a sense that in the fog of the world that we're inhabiting at the moment, with this, this disease, and all the questions about normal life, that actually pushing through it is something like this project, which is carrying on to a quality, and with attention to the craftsmanship that's involved in it that's totally timeless.

♪ And also a sense that this building has been standing here for all these decades, and has seen World War I, World War II, the 1918 pandemic, seen it come and go, the Spanish flu.

And still, it stands.

♪ It gives you a real sense of perspective, which feels really precious right now.

♪ So, somehow, even now, it feels like Big Ben manages to capture the moment to represent something.

It's just a real sense of enduring resilience.

And it somehow makes you really remember that all of the troubles of this year will pass.

(fireworks exploding) And Big Ben will surge on.

♪ (Big Ben ringing) ♪ (energetic music)