He accused Alistair Darling and the "worriers" at the Department of Transport of dragging their feet despite widespread support from Parliament and the Treasury, who were "very enthused" about the �10bn scheme.

On Monday, Mr Darling announced government support for the scheme, which is set to link Heathrow in the west and the Isle of Dogs in the east and includes a twin bore tunnel between Paddington and Liverpool Street.

But he warned it was unlikely to be ready in time for the 2012 Olympic Games for which London is bidding.

Alistair Darling has given backing to Crossrail

Mr Livingstone dismissed this as "nonsense" and said it could be ready by 2010.

"If the Secretary of State got off his arse and pushed the Bill through, we could start some time towards the end of 2004 or 2005, we would have a chance," he told a City Hall press conference.

"My language is the language of Londoners.

"It is a complete nonsense to say that Crossrail cannot be ready in time for the Olympics as long as we have six clear years to build it - and it is nine years away."

He also accused the department of "time wasting and prevarication" and urged them to get the "planning nonsense" out of the way.

He said he did not understand why the government needed three years to prepare the Bill and analyse the business case for the line.

Ken Livingstone accuses the government of time wasting

The rail link is forecast to carry 200,000 people in the morning peak period and could create 100,000 jobs.

Transport minister Tony McNulty said that Mr Livingstone's own transport authority Transport for London (TfL) is part of Crossrail backers, Cross London Rail Links (CLRL).

He said CLRL has already submitted development plans: "Perhaps Ken needs to get off his own backside and read his own document.

"His own transport authority Transport for London form half of CLRL who have themselves advised that Crossrail will not be ready until 2013-14.

"What London needs now is for all sides to work together to make Crossrail happen rather than sniping at each other."

Consultation with the business community will begin this autumn to see the extent it is willing to contribute.

London's Transport Commissioner Bob Kiley believes there is sufficient business interest to provide 60-80% of the funding.