The first of the two new footbridges alongside Hungerford Bridge opened to the public at 6am on Monday morning.
Mayor of London Ken Livingstone attended a reception to mark the completion of the upstream crossing on Sunday and was given a tour of the new bridges which replace the single downstream walkway between the Royal Festival Hall and Charing Cross station.
The Hungerford Pedestrian Bridges are expected to carry around seven million people a year when completed by the autumn, when the downstream bridge opens in the Autumn.
Mr Livingstone said: 'This is a crucial crossing for London – that's why I decided to step in and help make it happen when the project was threatened two years ago. Improving access to London on foot is a priority. This crossing meets that need and gives Londoners another beautifully-designed bridge to add to a world-renowned collection.'
The Hungerford Pedestrian Bridges project has been promoted by the Cross River Partnership with funding from the Mayor of London, the Millennium Commission, Westminster City Council, Railtrack, Lambeth Council, the Railway Heritage Trust and the government's Single Regeneration Budget.