Ken: I will replace buses in Oxford St with trams

The £200million move will effectively pedestrianise one of London's busiest shopping streets.

The project, which will be paid for by two new commercial blocks at the western end of Oxford Street, will also see areas of Marble Arch grassed over and become part of Hyde Park.

Black cabs would be forced to pick up shoppers from adjoining streets, either side of Oxford Street.

Mr Livingstone hoped to start work on the the tram system after the 2012 Olympics, with the scheme to be completed by 2018.

Speaking at a debate held by property developers with fellow mayoral candidates Brian Paddick and Si‚n Berry, Mr Livingstone said: "If re-elected I intend to start installing a tram running the length of Oxford Street. There are some factors which pose difficulties but we have thought about it and there are ways of overcoming them. It will either be a shuttle tram or will be linked to the crossriver tram.

"We would demolish the gyratory system [at Marble Arch], handing part of it back to greenland and building two developments on part of it which will fund the project.

"People getting a taxi would have to use the roads running north and south of Oxford Street. We would phase the buses out slowly and maybe run some along Wigmore Street."

The Mayor has previously proposed a similar scheme - but abandoned it in the face of opposition.

Oxford Street is used by some of London's busiest bus routes, very few of which terminate close to it. For most it is a part of their route between different parts of London. Critics of the previous scheme had warned it would be virtually impossible to move buses off the street to neighbouring routes because they do not have sufficient capacity.

Just seven per cent of pedestrians in the West End use buses and 68 per cent would support a trafficfree West End, according to latest figures released by the New West End Company, which represents shops on Bond Street, Oxford Street and Regent Street.

The scheme is supported by both Mr Paddick and Ms Berry, although Ms Berry said she wanted to see the buses on Oxford Street immediately replaced by a bendy bus shuttle running from Centrepoint to Marble Arch.

Ms Berry has announced proposals to pedestrianise the whole of the West End once a week.

The three candidates also proposed redevelopments for the east end of Oxford Street.