A committee of MPs has warned that 2012 may be the last opportunity to hold the Olympics in Britain.

In a report on the feasibility of holding the games in London, the Commons culture, media and sport committee said that a "synergy" of factors makes the forthcoming cabinet decision on a London bid one of "fundamental importance".

The committee said that the availability of land in east London provided a unique opportunity which is unlikely to be available again.

This factor, coupled with the slim prospect of any other British city winning a bid, led the committee to conclude that a bid must be made now or never.

But while supportive of a bid in principle, the committee also expressed reservations about the potential cost of hosting the games.

"It is clearly desirable in principle that London should host an Olympic and Paralympic Games," the report said. "But it should not do so at any price."

The MPs, led by Labour's Gerald Kaufman, do not believe that the government has yet settled on an estimated cost for the games, or reconciled this against other priorities.

Any bid and spending commitments must be "justified in comparison with other sporting and wider spending demands on government", said the report.

And the committee also expressed doubts about the legacy of a bid being sustainable over the long term.

An Olympic stadium could become an expensive white elephant after the games, the MPs warned.

The report says that the stadium must be built with the option of pulling it down after the event if no long term plan can be developed.

London is already in the process of building a new stadium at Wembley capable of hosting the Olympics "without legacy issues", it says, leaving another stadium in east London "with an uncertain future".

The cabinet is due to make a final decision on whether to back a bid by the end of the month.

The latest indications, which the committee's report will not have changed, suggest that it is not likely to do so.

Both the prime minister and the chancellor are said to be wary of underwriting the cost of a successful bid, which could cost billions of pounds.

With northern MPs alarmed at the prospect of money being taken away from regional projects to be put towards the games, Jowell will enter negotiations with London mayor Ken Livingstone over how much money the Greater London Authority may be able to commit.