How Tower Bridge was built and why it is famous: the 1884 competition, the steel inside the stone, the bascules and the engines, the 1952 bus jump, and the London Bridge mix-up

Architecture · 4 September 2026

Tower Bridge crosses the Thames beside the Tower of London and was built between 1886 and 1894 to the design of the City architect Horace Jones and the engineer John Wolfe Barry, as a bascule bridge whose two leaves lift to let ships into the Pool of London, dressed in Gothic stone so that it would suit the medieval fortress beside it; it is 244 m long with two towers 65 m high, a steel frame of 11,000 tons under the granite and Portland stone, two bascules of 1,000 tons each that were lifted by hydraulic power from steam engines until 1976 and by electric oil hydraulics since, and two high-level walkways 42 m above the water that let pedestrians cross when the bridge was open. It is famous because it is the most recognisable bridge in the world, the only one of its kind on this scale, and because of the stories: the bus that jumped the gap in 1952, the colours of 1977, and the American who bought London Bridge in 1968 and is said, wrongly, to have thought he was getting this one. Below: why it was built, the competition, how it was built, how it lifts, its life since, the numbers, the Tower next door, and the myths, with the neighbouring White Tower in the Buildings by style collection and the style in Victorian architecture.

Why it was built

In the 1870s London had grown east of London Bridge into the docks and the East End, with a million people on each bank and no crossing below London Bridge except the Thames Tunnel of 1843, which carried a railway, and ferries; London Bridge carried 20,000 vehicles and 100,000 pedestrians a day and was jammed. A new bridge downstream would have to let tall-masted sailing ships and steamers reach the wharves of the Pool of London, the busiest port in the world, between London Bridge and the Tower, so a fixed bridge high enough for them would have needed approaches a mile long; the City of London's Special Bridge or Subway Committee of 1876 asked for designs, received more than fifty, from tunnels and lifting platforms to a rolling bridge, and argued for eight years. Tower Bridge.

The competition and the design

In 1884 the committee chose the scheme of Horace Jones, the City Architect who had built Smithfield and Leadenhall markets, for a bascule bridge, a drawbridge whose two leaves swing up on pivots like the drawbridge of a castle, with a central opening of 61 m for shipping, two side spans hung from the towers as suspension bridges, and, at Jones's suggestion, towers in a Gothic style to match the Tower of London, whose keeper had objected to anything modern beside it; the engineering was by John Wolfe Barry, son of the architect of the Houses of Parliament, who designed the steel frame, the hydraulics with the engineers Armstrong Mitchell of Newcastle, and the foundations, and who took over the whole job when Jones died in 1887, a year into construction, with the architect George Stevenson completing the stonework in a more elaborate Gothic than Jones had drawn. Parliament passed the act in 1885, with conditions: the opening must be 61 m wide and 41 m high, the bridge must open for shipping at any time, and the piers must not narrow the river.

How it was built, 1886–1894

• Piers. Two piers in the river of 70,000 tons of concrete and masonry each, built inside cofferdams of timber and iron sunk to the London clay 8 m below the bed, with the river kept open to shipping throughout by working on one half of each pier at a time; the piers took four years.
• Steel. A frame of 11,000 tons of steel from Sir William Arrol of Glasgow, who had just built the Forth Bridge: each tower is four steel columns 36 m high carrying the walkways and the suspension chains, and the bascules are steel girders 30 m long with 400 tons of lead and iron counterweight in the pier chambers; the frame stood complete in 1892 and the stone went on it.
• Stone. Cornish granite and Portland stone, 31,000 cubic metres, cladding the steel to make the towers look like a castle; the Victorians were criticised for it then and the stone is why the bridge is loved now.
• Workers. 432 men at the peak, from five contractors; ten died, mostly in the piers.
• Cost and time. 1,184,000 pounds, about 150 million today, from the City's Bridge House Estates, which has maintained the bridge and the City's other bridges from its medieval endowment ever since; eight years, from 21 June 1886 to the opening by the Prince of Wales on 30 June 1894.

How it lifts

The bascules pivot on axles 0.5 m thick in the piers, each leaf balanced by its counterweight so that the engines only overcome friction and wind: from 1894 to 1976 the power was water at 750 pounds per square inch pumped by two steam engines in the south-east pier building into six accumulators, tall cylinders with a weighted piston that stored the pressure, from which it drove the eight hydraulic engines in the piers that turned the gears and racks under the roadway; the leaves rose to 86 degrees in about a minute. In 1974–76 the steam and water were replaced by electric pumps and oil hydraulics that drive the original racks, and the old engines, boilers and accumulators are in the Engine Rooms museum. The bridge opened about 6,000 times a year in the 1890s and opens about 800 times a year now, on 24 hours' notice by any vessel over a certain size, free; the Pool of London closed as a port in the 1970s and the ships are now tall ships, cruise ships and naval vessels.

The walkways and the bridge since

• The walkways. The two high-level walkways were for pedestrians to cross while the bascules were up; they were reached by 200 steps or the lifts, and Londoners preferred to wait for the bridge, so the walkways became the haunt of pickpockets and prostitutes and were closed in 1910. They reopened in 1982 as the Tower Bridge Exhibition, glazed, with the view along the river, and in 2014 got glass floors 11 m long, 42 m over the traffic.
• 1912. Frank McClean flew a Short biplane between the bascules and the walkways, the first of several.
• 1952. On 30 December the bridge began to open while a number 78 bus was on it, the watchman having failed to ring the bell; the driver, Albert Gunter, accelerated and jumped the 1 m gap as the bascule rose to 2 m, landing on the north leaf, which had not yet moved; twelve passengers were hurt slightly and Gunter was given 10 pounds and a day off.
• 1977. For the Queen's Silver Jubilee the steel was painted red, white and blue; before that it had been chocolate brown, and since 2010 it is blue and white.
• 1997. The bridge opened for a barge while President Clinton's motorcade was crossing, splitting it; the bridge master said the barge had given notice and the president had not.
• 2000–2010. A ten-year repainting and refit; the bridge was closed for three months in 2016 for resurfacing and the walkways got the glass floor.
• Today. 40,000 crossings a day by 21,000 vehicles and 20,000 pedestrians, a weight limit of 18 tons, and about 800 lifts a year, listed on the website in advance.

The numbers and visiting

• Length. 244 m in all; the central span 61 m between the piers, the side spans 82 m each.
• Height. The towers 65 m; the walkways 42 m above high water; the opening 41 m clear when raised, 8.6 m when closed.
• Bascules. Two leaves of about 1,000 tons each with counterweights, rising to 86 degrees in 60 to 90 seconds.
• Materials. 11,000 tons of steel; 70,000 tons in each pier; 31,000 cubic metres of stone.
• Time and cost. 8 years, 1886–94; 1,184,000 pounds; 432 workers, 10 deaths.
• Lifts. About 6,000 a year in the 1890s, 800 now.
• Visiting. The Tower Bridge Exhibition, entered at the north tower, takes visitors up to the walkways and the glass floor and down to the Engine Rooms on the south bank, about an hour, by ticket; the road and the pavements are free; the lift times are published, and the view of a lift is from the Tower's wharf on the north or Butler's Wharf on the south. The Tower of London, HMS Belfast, the Shard and Borough Market are within a few minutes' walk, and the river boats stop at Tower Pier.

Versions and theories

• The American bought the wrong bridge. Robert McCulloch bought London Bridge, the granite bridge of 1831 that the City was replacing, for 2.46 million dollars in 1968 and re-erected it at Lake Havasu City, Arizona, in 1971; the story that he thought he was buying Tower Bridge was told at the time and he denied it, and the City's man who sold it, Ivan Luckin, said no one was fooled. It is the most repeated myth about either bridge.
• It is called London Bridge. It is not: London Bridge is the plain concrete bridge of 1973 upstream, on the site of the medieval one; Tower Bridge is named for the Tower of London, and the two are half a mile apart.
• It is medieval. It is a steel bridge of 1894 in Gothic dress; the Tower next door is medieval, and the bridge was designed to look as if it belonged.
• The bus driver was sacked. He was given a 10-pound bonus and a day's leave, and the story was in every newspaper.
• The walkways were closed for suicides. For lack of use and for the pickpockets; suicides were not the reason given.
• It still runs on steam. Steam and water until 1976; oil hydraulics and electricity since, driving the original racks and gears.

The bridges of the same age across the Atlantic are in how the Brooklyn Bridge was built, and the fortress the bridge was built to match in how castles were built.

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