The Millennium Bridge, officially known as the London Millennium Footbridge, is a steel suspension bridge for pedestrians crossing the River Thames in London, linking Bankside with the City of London. It is located between Southwark Bridge and Blackfriars Railway Bridge. It is owned and maintained by Bridge House Estates, a charitable trust overseen by the City of London Corporation. Construction began in 1998 and it initially opened in June 2000.
Londoners nicknamed the bridge the "Wobbly Bridge" after pedestrians felt unexpected swaying motion. The bridge was closed later on opening day and, after two days of limited access, it was closed for almost two years while modifications were made to eliminate the motion. It reopened in 2002.
The southern end of the bridge is near the Globe theatre, the Bankside Gallery, and Tate Modern, the north end next to the City of London School below St Paul's Cathedral. The bridge alignment is such that a clear view of St Paul's south façade is presented from across the river, framed by the bridge supports.
The design of the bridge was the subject of a competition organized in 1996 by Southwark council and RIBA Competitions. The winning entry was an innovative "blade of light" effort from Arup, Foster and Partners, and Sir Anthony Caro. Due to height restrictions, and to improve the view, the bridge's suspension design had the supporting cables below the deck level, giving a very shallow profile. The bridge has two river piers and is made of three main sections of 81 m (266 ft), 144 m (472 ft), and 108 m (354 ft) (north to south) with a total structure length of 325 m (1,066 ft); the aluminium deck is 4 m (13 ft) wide. The eight suspension cables are tensioned to pull with a force of 2,000 tons against the piers set into each bank — enough to support a working load of 5,000 people on the bridge at one time.
Ordinarily, bridges across the River Thames require an Act of Parliament. For this bridge, that was avoided by the Port of London Authority granting a licence for the structure obtaining planning permissions from the City of London and London Borough of Southwark. Construction began in late 1998 and the main works were started on 28 April 1999 by Monberg & Thorsen and Sir Robert McAlpine. The bridge was completed at a cost of £18.2M (£2.2M over budget), primarily paid for by the Millennium Commission and the London Bridge Trust. It opened on 10 June 2000 (two months late).
Unexpected lateral vibration (resonant structural response) caused the bridge to be closed on 12 June 2000 for modifications. Attempts were made to limit the number of people crossing the bridge. This led to long queues but was ineffective to dampen the vibrations. Closure of the bridge only two days after opening attracted public criticism of it as another high-profile British Millennium project suffered an embarrassing setback, akin to how many saw the Millennium Dome. Vibration was attributed to an under-researched phenomenon whereby pedestrians crossing a bridge that has a lateral sway have an unconscious tendency to match their footsteps to the sway, exacerbating it. The tendency of a suspension bridge to sway when troops march over it in step was well known, which is why troops are required to break step when crossing such a bridge.
The bridge was temporarily closed on 18 January 2007, during the Kyrill storm due to strong winds and a risk of pedestrians being blown off the bridge.