Tony Blair says he has not yet made up his mind whether or not to support a bid to host the 2012 Olympics in Britain.

He said the government would have to look carefully at the costs and whether a bid based in London had a good chance of winning the bid before reaching a decision.

Obviously it would be a great thing for the country to do Tony Blair

The Cabinet is expected to decide on Thursday whether or not to support such a bid.

But Craig Reedie, chairman of the British Olympic Association (BOA), has warned that unless the government throws its weight behind the proposal this week London's hopes of staging a summer Olympics in the future would be limited.

"If they turn this opportunity down, the land that's currently available in east London today will not be available on any reasonable basis after 2012," he said.

Good chance

Mr Reedie said he was confident he could win government support for the bid, which already has the backing of athletes including Sir Steven Redgrave, Paula Radcliffe and Matthew Pinsent.

But Mr Blair told BBC's Breakfast with Frost: "We need to study very carefully the stuff that's coming in, and the two basic issues are going to be affordability and have you got a good fighting chance of winning, because you're going to have to spend a lot of money and time in mounting the bid.

"Now you can't guarantee that you're going to win, but are you going to be a potential winner? That's what we're looking at now.

"Obviously it would be a great thing for the country to do but you've got to be sure that we're able to do it and that it's affordable. We better wait for the decision."

Livingstone believes 2012 is the UK's last shot at the Olympics

Mr Reedie said while he obviously could not guarantee Britain would win the bid to host the 2012 summer Olympics, he did believe it could win.

He said: "Nothing would do more for sport. Northing would move sport up the political agenda more than running a good Olympic bid and hopefully a successful Olympic bid.

"I have tried very hard to learn the art of not allowing my heart to rule my head. The BOA have put together one of the best alliances in favour of sport that I can remember in this country.

"We have presented the case to government pretty well and logic seems to determine that they would bite on this."

Ken Livingstone, the Mayor of London, says he has agreed a deal to share the cost of the games - which have been put at up to �2.6bn - and is increasingly confident about the city's chances.

The lottery operator, Camelot, is looking into ways of raising �1.5bn towards the cost of the event with a special game.

The rest of the money could come from a combination of the London Development Agency and council tax payers in the capital.