The pounds 93.8m scheme put forward by the Department of Transport would create six lanes in each direction at the busiest sections of the 121-mile orbital motorway, which is bombarded by more than 200,000 vehicles during peak hours.
It would include widening the M25 between junction 12 (the M3 exit) and junction 14 (the Heathrow airport exit) from four lanes to five on either side and, in the most controversial move, the Government proposes extending the section between junction 14 and 15 to six lanes in each direction.
John Watts, the minister for railways and roads, said: "These plans are an important step forward in the relief of congestion for this very busy motorway."
They were condemned by environmentalists and the Labour Party, who expressed concern that the proposals for an American-style super-highway on the M25 marked the end of attempts to find alternative solutions to London's traffic crisis, including the pounds 2.6bn plans for CrossRail, which would have created a new line linking the east and west of London.
Graham Allen, Labour's transport spokesman, said the expansion of the M25 was an outdated response to the traffic problem. "This pounds 100m motorway madness comes hot on the heels of the death of CrossRail. Londoners desperate for less traffic and better public transport will be asking the Government just what kind of priorities does it have?"
Mr Allen added: "Congestion on the M25 does need to be tackled, but this scheme will only generate more traffic."
Lynn Sloman, assistant director of the environmental group Transport 2000, described the proposals as "utterly futile".Reuse content