The mayor of London, Ken Livingstone, has risked the wrath of the green lobby by backing plans for the first new road bridge across the Thames for more than 10 years, linking Beckton and Thamesmead in a deprived area of east London.

Mr Livingstone announced yesterday that he would recommend construction of the £350m bridge at a board meeting of Transport for London on Tuesday, as part of a regeneration project intended to bring 25,000 new jobs to the Thames Gateway area.

He said the scheme was a "real opportunity for world-class urban development". But he risks running into a row over roadbuilding, which environmentalists insist merely creates more traffic.

Local businesses have been lobbying for the project, saying a chronic shortage of river crossings deters investment in east London. But environmentalists claim the bridge could become a polluted rat-run for commuters from Kent.

The Thames Gateway bridge will be the capital's first road bridge since the QEII bridge at Dartford, Kent, opened in 1991. Recent construction has concentrated on pedestrian bridges, with varying success - the Hungerford footbridges opened two years late and the Millennium Bridge was shut for alterations after visitors complained that it wobbled.

Julia Lalla-Maharajh, a director of the business organisation London First, said the scheme was crucial to creating employment in east London. "There's an awful lot of opportunity out there but the first step is to improve the transport infrastructure."

The following correction was printed in the Guardian's Corrections and Clarifications column, Tuesday November 19, 2002

We got into a double muddle when we said that the planned Thames Gateway bridge would be the first new road bridge to span the river since the QEII bridge at Dartford opened in 1991. We later referred to those crossings as the capital's road bridges.

First, the newest road bridge across the Thames is the Winterbrook bridge, part of the Wallingford bypass in Oxfordshire which was opened in 1993.

Second, Dartford is in Kent, not in London - the QEII connects that county with Essex. There has been no completely new road bridge across the Thames in London since 1933, when both Chiswick and Twickenham bridges were opened, although several replacements of older bridges have been built since then, most recently London Bridge in 1973.