The centrepiece of the Canary Wharf complex in east London - One Canada Square - was completed in August 1991 in the middle of a recession.
The 244m high tower was the tallest in Europe when completed and helped pave the way for a complete transformation of the London Docklands area over the coming two decades.
Design was led by consultant Yolles & Partners and construction by contractor Sir Robert McAlpine and the structure took three years to build. Principal architect was Cesar Pelli.
Some 27,500t of British steel and 500,000 bolts were used in the construction of the 50-storey tower, which holds 163,000m2 in fl oor space.
Foundation works got under way in 1988 with the plan to found the tower on 222, 1.5m diameter base grouted piles, capped with a massively reinforced 4m thick concrete raft. The geotechnical contract was reputedly worth £10M at the time. Piggot Foundations installed the piles, while Costain poured the slab.
Developer Olympia & York was responsible for the project from the late 1980s but the project ran into problems as Britain entered recession.
British firms showed a reluctance to relocate from the traditional financial centre within the City, and despite a personal promise by then prime minister Margaret Thatcher, the start of work on the Jubilee Line Extension, which now serves the site, was delayed.
As a result, the office space at Canary Wharf remained largely empty. Olympia & York went into administration in 1991, and the project was taken on by Canary Wharf Group.
The building is designed to sway 350mm in the strongest winds that might occur once every 100 years.
Clad in linen-finish stainless steel panels, the architect says the tower “reflects London’s grey and misty atmosphere”.
The tower joins onto a retail and assembly building, which includes shops and restaurants as well as a winter garden with adjoining meeting and exhibition rooms.
The lobby of One Canada Square also connects to the Docklands Light Railway station.
It held the title of Europe’s tallest for a brief period being overtaken by the 257m tall Messeturm building in Frankfurt - also completed in 1991. And in late 2010 The Shard at London Bridge overtook One Canada Square as the tallest building in Britain and formalised its position in March this year when it reached its full height of 310m.