The Secrets of London's Tower Bridge

Between Richmond and the North Sea, 30 bridges span the Thames. They carry people across a stretch of river 35 miles long, bringing together a population of nearly 8 million. These extraordinary structures have been the making of London, Britain's capital and, I think, Europe's greatest city. Millions of Londoners cross these bridges every week. Most, I don't suppose, give them a second thought, but for me, bridges are far more than merely means of transport, ways of getting from one place to another. They are also ways of linking the present to the past. London's bridges are not just functional objects, they're also symbols, metaphors. They transform, connect, inspire, and they tell great stories. Of Bronze Age relics on the Vauxhall Shore, of why London Bridge was falling down, of corpses splashing beneath Waterloo Bridge, and, above all, of the sublime ambition of London's bridge builders themselves. I was born when London was still one of the world's great ports and the Thames one of the world's great working rivers. I well remember, as a child, the impression that London's bridges made on me. I suppose bridges gave me my first thrilling, stomach-churning architectural experience, and, goodness me, they are doing the same now. Ah! Brilliant view! Some of London's bridges have vanished or been replaced. They are ghost crossings of the past, but each of them is a clue to the city's hidden history. In some ways, they are that history, a history that's lasted nearly 4,000 years. In the beginning was the river, the Thames, the greatest, the longest river in England. 200 miles from its source, the river meets the tidal stream. The result is a landscape of marshes and islands, indeterminate and always changing. Only here, far downstream from the city of London, can you understand the elemental world of sand, mud, pebbles and debris that was the Thames before the city and its bridges were built. For generations stretching back over centuries, Londoners laboured in the marshes at now long-lost trades. Mudlarks and scavengers, toshers and dredgers, watermen and oyster gatherers, all gone and lost class. The river has always been a portal into the past. It's inspired artists and writers, none more so than Joseph Conrad, who wrote that nothing is easier than to evoke the great spirit of the past. And upon the lower reaches of the Thames, from here Conrad could see the great modern city of London from an ancient perspective. The monstrous town was marked ominously on the sky, a brooding gloom in sunshine, a lurid glare under the stars. And this also has been one of the dark places of the earth. We live in the flicker, but darkness was here yesterday. The marshy landscape on the banks of the Thames gave birth to London, but the earliest bridge was built not here, but 15 miles upstream to the west, past the city of London, beyond the seat of power at Westminster, at a place which today we call Vauxhall. Here, in 1500 BC, before Troy fell and long before Julius Caesar came to Britain, the people of the marshes made a first attempt at a crossing. We're extremely lucky. Today, the remains are only completely exposed twice a year, at the very bottom of the spring tide. But what a find! Tests have shown that these timber piles have been preserved here for 3,500 years. So you've had this dated with dendrochronology? So you're absolutely there for sure? It's 1,500 years calendar-dated BC, yes. 1,500. So BC, which is about 3,500 years. So, therefore, this, in a way, is the oldest sort of in-situ bit of structure in London, isn't it? Why did they build this bridge? Some archaeologists think it carried people not across the river, but to an island that probably existed in the stream. We can't know for sure, but Gustave and his team think that, back then, this was the highest point of the tidal stream. And it's also a place where three rivers met, the Thames and two of its lost tributaries, the Tyburn and the Ephra. That's obviously magical, three rivers meeting, so weird and wonderful tidal things happen, I suppose. That's right, and if this was the tidal heading of the Bronze Age, that's a very magical place, because the moon is definitely saying when the tide will be low and when it will be high. And when people see this connection between those things in the sky, you know, the moon, and those things on Earth, the river, they connect, you know, as a sacred thing. You'd need to placate the river because very high tides would flood any settlements you had round here, so we have possibly a sort of sacred river at this point. When the bridge was discovered, the archaeologists found two bronze spearheads driven point down into the mud beside the bridge. Were they offerings to the deity of the river? Like coins in the fountain, this urge is universal, and even today Londoners continue to make offerings. All the way up and down the Thames these days, we find this kind of stuff. Now, these are not Bronze Age, these are Diwali lamps. Oh, my goodness me. It's like in India, it's like in the sacred Ganges. Hang on a minute. They're modern, they're modern. What's that? Lord Ganesh. Overcover of obstacles, great fellow. That looks like Krishna or something, doesn't it? And these chaps? They look like Krishna, doesn't it? You found these in the Thames. So Hindus living in England, in London, are using the Thames like the Ganges, a sacred river. Right, so they're replicating what we used to do in the Bronze Age. A ritual river, a powerful god. If Gustav is right, this challenges a lot of our assumptions about what bridges are for. It didn't originate as a means of transport or trade, but as sacred creations. This was a bridge between a spiritual, not a material, divide. A bridge between worlds, a bridge between the world of man here and the world of God, between life and death. The Thames was like the River Jordan. To cross it was to cross to a promised land. The link between bridges and the sacred echoes through the millennia. This bridge here is in fact commemorated in our language. The head of the Roman Catholic Church, the Pope, is called in Latin the Pontifex, which means both bridge builder and priest. Indeed, it was the Romans, about 1,500 years after our Marsh people's activities here, who built London's first traditional, conventional bridge. Bridging the Thames is not easy. The riverbed is changing all the time because of tides and currents and human activity. But in truth, it's very shallow, sometimes less than two metres deep at low tide. The Romans knew this. They were the champion engineers of the ancient world. They put their bridge on the shallowest, narrowest part of the river, now spanned by the modern London Bridge, right next to the ancient port, what is called the Pool of London. The consequences have been immense. For centuries, this area was the heart of the British economy. The key reason for that is that this was the first place upstream from the sea, about 40 miles in that direction, that a bridge could be constructed to connect the south and the north banks of the Thames. In addition, hard by the bridge is a tidal pool, allowing large ships to anchor, very good for trade. There's been a bridge here on and off for nearly 2,000 years, and that's been the making of London. Because of the crossing, London became an explosively successful settlement right from the beginning. So successful, in fact, that only when building work takes place can we get a glimpse of the Roman foreshore. As conquerors, the Romans needed a defensible riverside site and port, so that reinforcements could be rushed in if needed, and an evacuation could take place at speed in the case of an emergency. The trauma of Boudicca's rebellion in 1861, when the Roman capital of Colchester was burnt, combined with the fact that already at that time the bridge here made London the transport centre of Roman Britain, meant that when Roman authorities were established, London, not Colchester, became the provincial capital. From here, the Romans could control England, and they did that for several centuries. You're looking at a slice of Roman London, or the beginning of a slice of Roman London. The very first of the first century waterfront would have come through roughly where the guy down there is digging. We're looking south at the moment towards the river, so it would have cut across more or less there. So you can see we're only just beginning to uncover... We've only been here a couple of days, but you can see the difference between this modern stuff which they're digging out and the actual layers of archaeology which is left, and that's what they're trying to do. They're trying to distinguish real archaeology from modern rubbish. This is the first chance we've had to investigate the Roman bridge for more than 30 years. As far as we could make out, we only saw one pier of the bridge in 1981, but quite a lot of it. It's formed of a combination of horizontally laid timbers stacked on top of each other, cantilevering out, and then the actual bridge platform, the deck, is laid along the top of that. So that's, using the evidence of what we actually found in the ground, how we speculate the bridge would have looked. Fascinating. As the excavation continues, the archaeologists begin to find wooden piles, survivors of nearly 2,000 years of urban development. Can't resist coming to grips with Roman engineering. There's the pile. Ooh, very solid. These battered stumps are the remains of the wharves beside the bridge through which the goods of empire float in and out, changing the physical geography and economy of Britain forever. But the invaders never forgot that a bridge was still a sacred metaphysical place too. When the Georgians built the predecessor to the bridge I'm standing on, they dredged the riverbed to clear the bottom for ships to pass. Out there, in the middle of the river, they found a large cache of Roman coins, rather like these wonderful things, bronze and brass, and maybe silver. Archaeologists believe there was a shrine in the middle of the bridge where the Georgian people passing over would cast coins into the mighty Thames to appease its power. So, for the Romans, as with the Bronze Age marsh people upstream at Vauxhall, bridges were sacred things, things of religion. Have to remember, of course, that in Rome, the same word was used for a bridge builder as for a priest, pontifax. Indeed, it was one of the titles of the Roman emperor. Both emperors and empire are, of course, long gone, and the bridge with them. For centuries, there was no attempt to rebuild it, and no real need. The main settlement in London now was a long way from the remains of the Roman bridge. A mile and a half upstream, around what is now Covent Garden, a new trading post grew up by a sharp bend in the river. It was a beach market town, and the London street names preserve its memory. Of the Strand, where early English merchants pulled up their ships, and the Old Witch, the old vicus, or trading port. And the river became, as it had been before the Romans, a frontier, a border between warring kingdoms, with names like Essex, Middlesex, Surrey and Kent. For London to achieve its destiny as a great city, it needed a proper bridge. Once King Alfred and his successors had reunited England and reoccupied the Roman city, a bridge was built. But it was really no more than a flimsy causeway, intended more to stop raiders travelling upstream than to be an aid to transport. For a proper and solid bridge, London had to wait around 1,000 years after the Roman bridge. But then that bridge was very solid and very proper indeed. Of all the river crossings in London, the one we actually call London Bridge is the most famous, the one we remember in the nursery rhyme. But the structure immortalised in the song is not the ruthless concrete span we see today, nor even the one that preceded it. The bridge we remember is the medieval bridge, the bridge of Thomas Beckett and Dick Whittington, the one Chaucer and Shakespeare knew. But it's a ghost which haunts me still. And the question I ask myself is, what was it really like? What was London Bridge and why was it falling down? To find out, we have to go back 800 years to the 12th century. At the time, London was booming. Much of the street plan of the modern city was laid down by then, although very few of the actual buildings survive. But what has endured are the records of the bridge, preserved in the archives of the Corporation of London. They tell us that in 1173, a religious community, the chaplains, brethren and sisters of the Bridge of London, were entrusted with building a new stone bridge. And the mastermind of the project was a parish priest, Peter of Colchurch off Cheapside. These ancient documents offer insights into the creation, the use and maintenance of one of London's greatest structures, Old London Bridge. Started in 1176, it's been long lost. But this treasure trove of intimate and evocative documents almost bring it back to life. Look at this wonderful thing, for example. It is a grant dated 1205, a grant from Peter the Priest, Peter of Colchurch, the architect, the creator of London Bridge. Incredible. And attached to this grant is something utterly wonderful. It's a seal. Here it is. And it shows Peter of Colchurch, not as an architect or engineer, but as a priest offering communion. Absolutely wonderful. Such a direct connection with the main man behind Old London Bridge. Now, this is a charter of about 1320. And we have attached to it here another seal. Again, wonderful. It shows an abstract representation of the bridge, I suppose. Just simply an arch with Thomas Bickett sitting on the top of it. And below the arch we see the city of London. Absolutely wonderful image. St Paul's in the centre, Old St Paul's with its spire intact, flanked by city churches with their spires pointing to the heavens. One of the reasons the medieval London Bridge became such an icon for the city was that it was a living bridge, an astonishing structure with houses and shops built upon it. The oldest image of it dates from the 15th century. Here we see it. It's the first sort of drawn image of London Bridge. In the foreground, the Tower of London, with various activities going on, and there's the Watergate from the Thames. And in the background, an incredible image of the northern half of London Bridge, a great chapel in the centre, and the arches connecting that to land, the North Bank. And in the background, there's one kind of similar image to it, that on the seal, a skyline of London with the spires, Old St Paul's, and the spires of the city churches. It's a wonderful thing, this drawing. It's a manuscript drawing. In our search for Old London Bridge, the street plan of the city is a major clue. We know that the medieval bridge lay just to the east of its modern counterpart. And if you decode the street plan, its ghostly location begins to reveal itself. The monument to London's Great Fire of 1666 was put up beside the ancient northern approach to the bridge. And at each end of the bridge, we're told there was a church. Following the road here, Fish Street Hill leads us down to the church of St Magda's Martyr, which stood like a kind of spiritual tollbooth at the northern end of the bridge. Once you understand that Old London Bridge stood slightly to the east of modern London Bridge, everything here makes sense. This splendid elevation on the tower of St Magda's, the martyr church, which everybody crossing London Bridge would have passed because the carriageway, the roadway to London Bridge, was here. And inside there, within the arch, so to speak, below the tower, was the pedestrian route. And here we have salvaged some of the stones from Old London Bridge. I suppose they're part of the mid-18th century recasing of the bridge in Portland Stone. Inside the church is something of a relic, our next clue to what Old London Bridge might have been like. This wonderful model shows London Bridge as it could have looked, as indeed I'm sure it did look, in about 1400. It was then 900 feet long from the city here to Southwark, with the carriageway, the roadway, carried on 19 stone-built arches, the 20th arch being, in fact, the drawbridge, somewhat in the middle. And on the stone-built arches we have an array of timber-built houses and shops, about 140 in 1400. Also, one can see very clearly that about half the width of the river is constrained by thick piers of the arches and the breakwaters in front of them. They're called starlings, with the edges protected by timber piles. In the middle, roughly, is the great fortification, the drawbridge. I'm reminded that London was defended to a degree by the Thames. It was like a moat, and to span it was to compromise the ventures of the city. So one needed to prevent invaders coming across the bridge from the south. Up comes the drawbridge. This is the fortification. The bridge, in a sense, is part of the defences of London, along with the city wall. I don't know, one just wonders, can anything of this wonderful bridge still survive below the waters of the Thames? It was 30 years before this legendary crossing was completed, in 1209. It stood longer than any other in London's history. But like all bridges, it was never really finished. To resist the huge force of currents and tide on the river, it had to be maintained. And that offers us a clue to the real meaning of the nursery rhyme. What we have here, bizarrely, is what the cut waters, the piers for London Bridge, would have looked like, the medieval bridge. They would have been roundwood piles like this. Made out of what, chestnut or oak? Elm. Elm. Often. Driven in with a ram. Yeah. And then clad behind with timber planking. That would have been made up with masonry, with earth, with all sorts of solid things in between the timber planks and beams. So the bridge would be supported by the infill of these artificial islands, held in place by planks and roundwood piles. Very laborious work. But when do these date from? These are contemporary with probably the last phase of the medieval bridge. These would have been here in the late 18th century. The obvious question for laymen is, these piles are some centuries old. They survived underwater. At low tide, at high tide, water's right up here. It's astonishing. So timber is preserved by being kept wet? Yes. If it's kept wet, it'll be preserved. If it's kept dry, it'll be preserved. The real problem is if a timber rises from the bottom above the high-water mark, it'll decay at the high-water mark because part of it is dry and therefore doesn't expand. Part of it is wet and therefore it expands when it's wet and then it shrinks when it's dry. It took huge quantities of timber and Kentish ragstone to maintain Old London Bridge. The enormous costs were paid for by the proceeds from tolls from both people and ships. But sometimes the money went astray and the result could be catastrophic. In 1282, five of the arches of the bridge collapsed. About 12 years earlier, King Henry III had given the revenues of the bridge to his wife, Preet Eleanor, and she'd spent it on herself, not on maintaining the bridge. That's why London Bridge collapsed. She is the My Fair Lady of the Nursery Rhyme, a nursery rhyme which reveals Londoners' deep anxiety about the future of their all-important bridge. If it wasn't properly maintained on a regular basis, it would indeed collapse. After the disaster, there was a small revolution. The City of London took back the revenues of the bridge from the Crown and gave them permanently to the people, indeed to the successors of Peter of Colchurch's community, now called the Bridge House Estate. The bridge now symbolised London's newfound civic independence, but its religious roots were not forgotten. There were churches at each end, and in the middle was a chapel on two levels, one at the roadside for travellers and one at the water's edge for boatmen. Spiritual tolls were paid then and now. Every year on the Feast of the Baptism of Christ, which is in January, we process from this church to the middle of London Bridge, and there we meet some of our friends from Southwark Cathedral coming the other way. We have a short service in the middle of the bridge. We pray for people who work on the river, who take their recreation on the river, for people who have drowned in the river indeed, and then we throw a wooden cross into the river itself as a sign of God's blessing. These youngsters, too, are a direct link to that medieval world because the organisation which built and preserved Old London Bridge still exists. It has an income of £700 million a year, derived from centuries of investment. It is still responsible for all the bridges within the bounds of the city, but they have an annual surplus of up to £20 million, which goes to London charities, like this dance group, funded directly from the tolls and charity left by medieval Londoners all those centuries ago. Old London Bridge stood about 15 metres over there. With its tall buildings, its houses and shops, it was, in a sense, a city within the city. In that space, people, Londoners, lived and died, toiled and took their pleasures for nearly 600 years. I live nearby, and I often come here to look, to imagine the spectral bridge, to listen, to see if I can pick up the sound echoing through the centuries of the pilgrims, the merchants, the travellers, the soldiers crossing one way and the other. It may seem fanciful, but who knows, perhaps, perhaps... For 600 years, London Bridge dominated the city, and the massive iconic structure redefined the very river it spanned. Its huge piers and starlings interfered with the flow of the Thames itself. The blockage caused by the bridge slowed the current. As a result, the river regularly froze over. Londoners took to the ice with gusto, and what were called frost fairs, with games and processions, stalls and even bull baiting, became a London institution. By holding back the water, the piers of the bridge also functioned as a giant weir. In even the earliest manuscript, we can clearly see the rapids pouring through the arches. Passing through it was known as shooting the bridge, and boats were often overturned. Famed by the archers of London Bridge, the Thames became a theatre for royal pageantry. The more unpopular wives of Henry VIII shot the bridge as a rite of passage, rather than being given more conventional coronations. And later on, royalty travelled on the Thames in wonderful barges such as this. This splendid thing was made in the 1730s for Frederick, Prince of Wales. And, of course, ordinary Londoners enjoyed the Thames as well. There were frost fairs, firework displays, and the Lord Mayor's show was originally held on the water. Like Venice, London was a world of the water. The whole city faced the foreshore. Here in Greenwich, downstream from the city of London, you can still catch a sense of how the river and city once merged. Here stood one of the great Tudor palaces, right on the water. Rebuilt by the Stuarts from 1610 onwards, Greenwich never lost its river focus. It's a relic of the world of the Royal River, the world which it's seen would last forever. But London's growth changed all that. As industrial revolution swept onwards, London planned more bridges, bridges made possible by new technology. This volume contains visionary proposals for Thameside London. They'd drawn up in 1800 for the City Corporation, which at that time wanted to reorganise the Port of London. That involved rebuilding London Bridge and moving it significantly to the west. This shows a rebuilt London Bridge. This is the central arch, cast iron, much higher, so greater clearage for, indeed, High Mastership shown going through. This is an amazing image. Incredible. Of course, this did not happen. But things have gone, things have happened, all has changed. Changed to a large degree, brought about by engines such as this. This is a drawing of a piledriver, designed in the late 1730s for the construction of the foundations of Westminster Bridge. This is an early product of the Industrial Revolution, I suppose, because here you see horses. It says horse-powered, going round as a capstan, with a gear device to increase the power of the horses. Ropes would rise, this great hammer up here. There it is, this hammer's brought up the top here. Then it would be released and rushed down, pow, and drive the timber pile into the riverbed. So a very important movement in bridge construction. The Industrial Revolution, of course, transformed London, transformed the world, and very particularly for London. It fuelled an explosion of bridge construction. For more than 500 years, London Bridge stood alone at the crossing of the Thames. It defined the original city, the commercial giant. But two miles upstream was another big urban centre, Westminster. From 1300 onwards, this area had been the seat both of political power and social prestige in England. But it had no bridge. That's because the City of London had fought to preserve Old London Bridge's lucrative monopoly. So when plans for another crossing at Westminster were mooted, in the 1660s, there was uproar. It wasn't just the city fathers who objected, they were joined by thousands of watermen, that's boatmen and ferrymen, who believed their livelihoods would be threatened if a second bridge was built. Must remember that then, unlike now, the Thames was London's main highway, packed with crafts of all types, carrying goods from people up and down and from side to side. Now, the watermen were a very powerful lobby indeed. They had their own city livery company and even their own poet, the waterman poet John Taylor. He complained about the competition after the introduction in Tudor times of the sprung carriage. Carriages, coaches, jades and Flanders mares Do rob us of our shares, our wares, our fares Against the ground we stand and knock our heels Whilst all our profit runs away on wheels They couldn't charge more than the set fare, as taxis do today. But if you could persuade your passenger that it was against the tide and it was a terrible evening and whatever, and I'll do my best to get you there on time, then, of course, there might be a nice tip at the end of it. Indeed. OK, so the watermen were involved in many things, but one, of course, was getting people across the Thames. In a sense, bridges were the enemy of watermen. They took away the trade. Absolutely, yes. And they objected to them. They objected to every bridge and were compensated very often for, or at least the company was compensated very often for a bridge being built, taking trade away. Would you still object for yet another bridge being built? Did the watermen's company object to the recent Millennium Bridge? Oh, absolutely, yeah. You did? Oh, yes. Excellent. We thought that was hilarious. We call it the wobbly bridge. The wobbly bridge, yes. Indicated, wobblier than going... But seriously, I mean, you would object. Did you object to that bridge? Yes, much more venomously in the past, but we still say, you know, you don't need another bridge there. It was only in 1736, after centuries of argument, that Parliament agreed to a bridge at Westminster. Under the Act, the watermen got £25,000 compensation, the equivalent today of more than £2 million. When Westminster Bridge officially opened in 1750, London was transformed once again. The Thames had been a kind of moat protecting the city. Now all that changed. The commercial and political powers north of the river, once represented mainly by the church, now took charge across the river. And so started the dramatic transformation of the south bank of the Thames. Traditionally, the south bank had been a place independent of the city on the north bank, a place free of the city's controls and statutes. It was, I suppose, a land of liberty and libertines. There were theatres, bear-baiting pits, brothels, market gardens and pleasure grounds. But now it became something quite different. It became, in a way, a province of the north bank of the Thames, largely because, perhaps ironically, one of the major landowners and developers of the south side of the Thames was the City Corporation. The city and the bridge house estate owned land across the river, which jumped in value once Westminster and then Blackfriars Bridge were built. And the obelisks they erected here planned to be the focus of a grand new urban district that marks the centre of their holdings. As a result of the new bridges, London, north and south of the river, had become one great city. The new crossings were a distinctive part of what was to be the zenith of Georgian London. But like the Roman and medieval bridges before them, they too are now ghosts, swept away by development. Flying 14 miles upstream, however, we can experience their effect. Richmond Bridge, a classic 18th-century masonry arch structure, is the only one of London's Georgian bridges to survive. And it sits in a green riverside landscape, a middle-class suburb surrounded by aristocratic houses and parks. It allows us a glimpse of what Westminster might have been like when the bridge was new, and the idea of London as a river city was at its height. Early one morning in September 1802, William Wordsworth passed across Westminster Bridge on the top of a coach. He was inspired by what he saw. It was a vision. He wrote a poem, and the poem, in the most charming way, is here on this bronze plate upon Westminster Bridge. Earth has not anything to show more fair. Dull would he be of soul who could pass by a sight so touching in its majesty. This city now doth, like a garment wear the beauty of the morning. Ships, towers, domes, theatres and temples lie open unto the fields and to the sky. Standing here, I can see the city as Wordsworth saw it. It haunts my imagination, Georgian London, one of the greatest urban creations ever achieved by mankind, I argue. And to think that from here, that great city unfolded itself to Wordsworth in a way he could not resist. Wordsworth's poem was actually a swan song for Georgian London. Between 1750 and 1850, nine bridges were thrown across the Thames. But despite this, the city began to turn its back on the water as a population of more than 2.5 million pushed further and further away from the riverbanks. London was fast becoming an industrial megacity. It needed rapid transit and bridge builders like John Rennie. Rennie built three great bridges, Southwark Bridge, Waterloo Bridge and a new London Bridge. But sadly, none of them survive. So, like Old London Bridge, you have to search for Rennie's Bridge. This is part of the southern approach to Rennie's London Bridge. It's a fragment that offers a glimpse of the character, of the power, of the whole. A reminder of the architectural engineering wonder that we've lost. I love the bold classical corners and the tremendously strong granite walling. It all has a Roman solidity and grandeur. Rennie's new London Bridge was his final work. It was built alongside the medieval bridge. New roads had to be built, much demolition was carried out and the historic street plan of London was changed. Although, to my mind, it never rivaled the medieval bridge, it too became a signature of the city, famous enough to be dismantled and sold to rich Americans in the 1960s. The whole structure was rebuilt stone by stone to grace a housing development in the Arizona desert. I must be going, no longer staying The burning towns I have to cross The new bridges reduced London's reliance on the river even more. Once it was common to row on the river at night, like this. Not any more. Success came with a price. The 1840s and 50s were grim years in London's history. The population of the city had swollen. London's infrastructure couldn't cope with the megacity London had become. The river was filthy, polluted on sewage and industrial waste. It was poisoning Londoners. It was killing them in their tens of thousands. Waterborne diseases like cholera was rife. The city was poisoning the wells of London and killing its population. The bridges shared in the sickness. Waterloo Bridge became notorious for suicides, particularly for despairing women jumping from its parapets. And statistics confirm its reputation. In the 1840s, about 15% of London's suicides jumped from Waterloo Bridge. This aspect of London's bridges and the Thames as theatres of death is etched into our literature. Charles Dickens in our Mutual Friend, essentially a novel about the river and river life, starts the story with these characters fishing in the Thames for corpses, a valuable commodity. London had now become the capital of a world empire, the largest, richest and most powerful city in the world. And yet it was awash with disease and poverty. Something had to be done. The solution was a brutal taming of the Thames itself. An embankment, which contained not just a giant new sewer, but a railway line as well, was the work of one of London's great engineers, Joseph Bazalgette. I'm standing on the Victoria Embankment. In front of me and above me is the Hungerford Bridge. Below me is Bazalgette's mighty sewer, the Underground Railway, a gas mains and a telegraph cable. This was and remains spectacular engineering. When completed, London would never be the same again. This was the death knell of the riverside, almost Venetian-looking London. Grand buildings like Somerset House once had spectacular watergates where, at high tide, people and goods could arrive by boat. But Bazalgette built a vast wall to separate the river from the city. Inside it, 22 acres of land were reclaimed, pushing the river back in places by more than 100 metres. This 17th-century watergate is the last surviving relic of the old waterfront and is now marooned on the edge of embankment gardens. You can clearly see it in this painting, which shows just how splendid the Georgian waterfront must have been. Safer transport and cleaner water came with a cost. The legacy has been really rather appalling. It's cut off the river from the life of London and the great riverside boulevard, wonderful, with horse-drawn traffic and pedestrians, is now noisy and polluted urban motorway. And the buildings that once rose from the river, like Somerset House behind me, rose like palaces in Venice, and rise from swathes of traffic. So, really, the embankments had a terrible effect on the city. It's one of the reasons why Londoners, in a way, have forgotten the wonders and beauty of the river. Nonetheless, Victorian modernity still had its triumphs. Hammersmith Bridge, in the western suburbs, is one of them. It's one of three built by the same Joseph Bazalgette. Unsurprisingly, construction at Hammersmith employed the latest technology. It's a suspension bridge with the roadway supported from above rather than below, unlike traditional arch bridges. The road hangs from wrought-iron cables strung over cast-iron towers, with each end anchored firmly in the ground. It's a wonderful looking bridge. It's a window into mid-Victorian London. The engineering, of course, epitome of Victorian engineering, a combination of beauty and of incredible strength. Cast iron, very strong, as they say, in compression, pushing down very strong. That's good, perfect for the suspension towers. But the chains, of course, they have to be a bit more elastic, so they have a tensile strength, hence wrought-iron's use. So, wonderful, again, doesn't seem much now as a casual observer, but a lot of engineering technology going on here. Functional, strong, also beautiful. And in cast iron, of course, you can cast lovely detail, hence the suspension towers having some classical detail at the top, cornices and various canvases leaves, rather wonderful mouldings. So every time you look at this bridge, you can read more into it and understand more about the wonder of the engineering in Victorian London. It's a complete Victorian piece, one of London's best bridges. I love it. Bazalgette's triumph at Hammersmith was commissioned by the newly created Metropolitan Board of Works. The Board was the first overall government for the new Victorian megacity. In 1869, it had taken over all the private bridges across the Thames and abolished all the remaining tolls. And it was determined to proclaim its authority. I love the ornament on this bridge, the iconography, it's so revealing. Look, for example, this wonderful piece of old heraldry, I suppose, behind me. In the middle is a royal coat of arms. To the left, the arms of the city of London. On the right, the arms of the city of Westminster. But also the arms of Kent, of Surrey, of Middlesex and of Essex. This bridge really defines London as it was in the late 19th century. It also reveals the power of bridge building. London was no longer simply a city, it was a city-state. By the 1890s, Bazalgette and the Board of Works had shaped the city, preparing it for the 20th century, and with it, the climax of the British Empire. The city of more than 5 million people stretched down both banks of the Thames. But for more than half that distance, from London Bridge to the sea, there were still no bridges, just dangerous and expensive tunnels. They were dug because, despite all the changes, London was still a port. Indeed, it was the greatest port city in the world. And a bridge would prevent big ships from coming upstream. The docks downstream, the West India Docks and Catherine's Dock, had been constructed in the early 19th century. But in the late 19th century, London's traditional port, the Port of London over there, still functioned. The ships moored several deep into the Thames, some almost as large as they did in Belfast over there. So any crossing of the Thames downstream from here had to allow the largest of ships still to reach the pool. Everybody had their own idea of how to solve the problem. Two architects contributed different swing bridge plans. Another contemplated a tunnel under the Thames. Yet another hoped to build a transporter bridge which lifted people in traffic high enough to let the ships through. But the winning plan returned to a feature of the legendary medieval crossing, a drawbridge. The completed tower bridge deployed a vast hydraulic system powered by steam engines to pivot the entire roadway to let ships sail through. In the bowels of the structure, the scale of it all becomes clear. This vast cavernous space is a bascule chamber below the south tower. Walk level is roughly here. And above me is the underside of the roadway. You can hear the traffic echoing. Everything that's painted white moves. So when the tower bridge roadway goes up, the white elements here, that's the counterweight, come down to occupy this space. It must be very scary to see that. Amazing. Of course, this is a bridge like no other in London. It's a moving bridge, a living bridge, in a sense, with the crew, people in control rooms, machinery operating it. Living, vibrating, almost speaking. I can hear it. But all of the engineering expertise was invisible in the completed bridge. Instead, the architecture was deliberately designed to merge with the Tower of London next door. This is one of the most astonishing things about Tower Bridge. It's not a Gothic structure built out of stone, but it's a steel-frame structure, a modern building. And through this window, you can see exactly what I mean. I'm looking at the companion tower to this one, outside all this wonderful Tudor Gothic finials, these lovely ornamental details, all designed to fit in with the ancient Tower of London. All history, and in here, all this modern steel. A functional building. Very strong. Very, very sort of, I say, almost brutally honest in its construction. Inside, outside, all this ornament. History, beauty, pedigree. Evocation of dreams of the past. Hiding the brute functional realities behind a Gothic façade may have been a triumph of late Victorian genteel propriety, but the effect was to create a sense of immemorial age. That is, it had always been there. Old London Bridge, with its houses and shops, had been a unique icon of London. Now the city had found its successor. Tower Bridge, the imperial city's gateway to the massive docks downstream and its vast empire beyond. After 150 years of frantic bridge building, London had reinvented itself. After so much of late Victorian and Edwardian Britain, London's bridges were sort of steeped in nostalgia, instantly historic. Look at Tower Bridge, utterly amazing. Now there was to be a century of quiet on London's river, apart from two bridges built far upstream. A quiet that seemed timeless, as T.S. Eliot observed, as he, like me, slipped quietly downstream in the wasteland. The river sweats, oil and tar. The barges drift with the turning tide. Red sails, wide to leeward, swing on the heavy spar. The barges wash drifting logs down Greenwich Reach, past the Isle of Dogs. By the end of the 20th century, the vast sprawl of Greater London meant travellers now had to be able to go round it as well as through it. At the time this heroic bridge at Dartford was completed in 1991, carrying the orbital motorway across the Thames, engineering had moved into a new league. Between the towers is three times as long as Old London Bridge and runs 57 metres above the water. It's among the largest bridges of its kind in the world. Dartford's a cable-stayed bridge. This is not the same as a suspension bridge. Here the forces of loads travel up the cables and then directly down the towers, unlike a suspension bridge where they are anchored on each bank. This is a more stable design. It allows for the creation of vastly wide and high spans. This is a bridge that's making a statement. What's it saying? Well, it's proclaiming that the whole of the Thames estuary belongs to London. Crossing the Thames far downstream from the historic city, Dartford Bridge defines London as being larger than ever, a city-state within south-east England. The claims of the Board of Work, as displayed at Hammersmith, far upstream, now seem vindicated. Here you really do understand the nature of this bridge. It does command the estuary. It is this great gate. The approach to London is here now. The city over there, the sea over there. Ships come and go. My goodness me, I can just about see the towers of a canary wharf. But however magnificent the bridge is in itself, however modern, it doesn't erase the echoes of the past that so intrigued Joseph Conrad. I'm about 15 miles downstream from the Pool of London, where everything started around 2,000 years ago. There, of course, things have changed many times, but here in places like this, it feels well. Surely much as it did when the Roman triremes passed by. This is a strange location. Sort of seeming lost between worlds. A very odd place indeed. An edgy frontier yet emerging from the primordial ooze and mud and slime and the reeds, much as London emerged all those centuries before. Oh, now, this is why I love the Thames. It carries memories of all the people who have travelled on it, who have lived beside it. Look here, bits of pottery, porcelain, earthenware. Look at this lovely, delicate handle from a teacup, I suppose. Beautiful. There's such an intimate connection with the person who owned it, loved it, lost it. That's what's so incredible about this place, that it's a living connection with the ghosts of the past who stand here. One finds and connects and remembers. By AD 2000, London had lived through nearly 20 centuries of its own history and what better way to celebrate that history than with a bridge? But not a giant, a jewel, one designed not for transport but for human delight. A pedestrian bridge that opened up a new way through the city and, in a nod to its noble forebears, a spiritual bridge pointing directly to London's cathedral, St Paul's. Although it suffered teething troubles, the design, by engineers Ove Arup, architect Norman Foster and even a sculptor, Anthony Caro, is a work of art. This bridge has redefined London once again by creating a new link across the Thames. It's brought added life to Southwark in front of me and the city behind me, creating a wonderful connection between Tate Modern up there and St Paul's Cathedral. Doesn't it look absolutely fantastic? Also, the bridge has created a spectacular new vistas of the city. From here, I can see an array of bridges to the left and to the right. Wonderful tower bridge over there in the distance. Also, a wonderful object. Lovely to walk across it, lovely to explore it, to touch it and look at it. It reminds me, in a way, of other great pedestrian bridges around the world. The Rialto Bridge in Venice, for example, also exquisite. It, of course, is lined with shops, a lovely living thing, the Rialto Bridge. It puts me in mind of inhabited bridges. I wonder if London could ever recapture the glory of Old London Bridge with its houses. Could there be a new inhabited bridge in London? Perhaps, perhaps. I hope so. People have been building bridges in London for 3,000 years or more and those extraordinary structures have defined the city. From the beginning, they were sites of primal spiritual power as man attempted to tame and harness the brute forces of nature. But they've also shaped London's economic and political dominance. Once a permanent bridge was built, wealth and power found their way to London and with them, the talents of millions of people. And so these crossings became not only a vehicle for royal and political display, they helped London become, to my mind, the greatest city in the world. There will be new bridges and different Londons in the future. Even now, a cable car bridge is being built downstream at the docks. That, like this bridge, can only be a good thing. It will help Londoners regain the pleasures of the Thames. Only through the Thames and its bridges can you grasp the true nature of London and understand those diverse people, costumongers and kings, warriors and merchants, who have made London the fantastic city it is.