Tower Bridge

By the late nineteenth century the growing population and trade of London's East End, home to 39% of London's population and once likened in size to "Manchester on the one side, and Liverpool on the other", had created demand for a new river crossing downstream of London Bridge. A conventional fixed bridge could not be built, since it would cut off sailing ships from the wharves of the Pool of London between London Bridge and the Tower. A Special Bridge or Subway Committee, formed in December 1875 under Sir Albert Joseph Altman, received more than fifty proposed designs, including one from the engineer Sir Joseph Bazalgette that was rejected for lacking sufficient headroom. In 1884 the Bridge House Estates Committee recommended a low-level bridge with a mechanical opening, and that October the Court of Common Council chose a bascule design over two swing-bridge alternatives. The enabling act, the Corporation of London (Tower Bridge) Act 1885, received royal assent on 14 August 1885; it fixed the dimensions of the piers and spans, required the design to accord architecturally with the Tower of London, and required it to open for shipping regardless of delay to road traffic.

Construction, funded by the City Bridge Foundation, a charity established in 1282 to maintain London Bridge, began on 22 April 1886, with the Prince of Wales laying the foundation stone that June. Sir John Wolfe Barry was engineer and Sir Horace Jones architect; when Jones died in 1887, Barry took over the architectural work, and his assistant Stevenson replaced Jones's original brick facade with the more ornate Victorian Gothic cladding the bridge carries today. Two piers containing more than 70,000 tons of concrete were sunk into the riverbed, not completed until January 1890 because work on the second pier had to wait until staging around the first was cleared to keep the channel open. More than 11,000 tons of steel went into the towers, clad in Cornish granite and Portland stone. On average 432 people worked on the site at any one time, at least 1,200 over the whole project, and ten men were killed during construction. The finished bridge cost £1,184,000.

Tower Bridge was officially opened on 30 June 1894 by the Prince and Princess of Wales, attended by the Lord Chamberlain, Lord Carrington and the Home Secretary, H. H. Asquith. The Corporation also gave a separate entertainment to the 1,200 workmen and their wives, presenting each man with a commemorative pipe and tobacco and each wife with a box of sweets. The new bridge carried no toll, and foot traffic quickly transferred to it from the nearby Tower Subway, one of the world's earliest underground railways; having lost most of its income, the subway closed in 1898.

During the Second World War Tower Bridge was a target for enemy action as a major route to the Port of London. In 1940 the high-level span took a direct hit that severed the hydraulic mechanism and put the bridge out of action, and in April 1941 a parachute mine exploded nearby, seriously damaging a bascule, the towers and the engine room. A third engine, built by Vickers Armstrong at Elswick, was installed in 1942 as insurance against further damage to the originals.

On 30 December 1952 the bridge began to rise beneath a number 78 double-decker bus after the usual warning procedure failed while a relief watchman was on duty. Driver Albert Gunter accelerated across the widening gap, clearing about six feet to land the bus on the north bascule, which had not yet begun to rise; the conductor broke his leg and twelve of the twenty passengers suffered minor injuries. The City Corporation rewarded Gunter's decision with a £10 bonus.

The bridge's Southwark section was Grade I listed on 6 December 1949 and its Tower Hamlets section on 27 September 1973. In 1974 the original hydraulic machinery, powered by steam-driven accumulators, was largely replaced by an electro-hydraulic drive system, with only the final pinions retained from the Victorian installation; the redundant 1942 engine went to the Forncett Industrial Steam Museum. Tower Bridge remains one of five Thames crossings owned and maintained by the City Bridge Foundation, carries more than 40,000 crossings a day, and still opens for river traffic on 24 hours' notice, free of charge, around a thousand times a year. Its high-level walkways, closed to pedestrians in 1910 and reopened in 1982, together with the towers and engine rooms, now form the paid Tower Bridge Exhibition.