London Briefing/Chris Johns:  London's campaign to host the 2012 Olympic Games is gradually moving up through the gears.

The bid has a new chief executive - the former middle-distance running star Lord Coe - with Barbara Cassani having fallen on her sword partly because, in her words, she felt that there was a greater chance of garnering votes from the international community if the effort was not headed up by an American.

The fall-out from the war in Iraq sometimes reaches into surprising places.

Britain can be a peculiarly pessimistic place. Much analysis of the bid is conducted in terms of its likely failure. Comparisons with the ill-fated Millennium Dome are rife: many analysts see another white elephant in the making.

Even if it succeeds, many people have gloomily concluded that the games will cost so much money that the chances of a profit are remote in the extreme.

Well known commentators have seized gleefully on recent research that suggests the only games to have turned a profit in recent decades were those held in Los Angeles some 20 years ago. Even games normally associated with success, like Sydney in 2000, lost money, according to some bean counters.

That the forthcoming Greek games are now estimated to have cost twice the original estimate, is simply grist to the sceptics' mill.

Doubters point to a long list of British public-sector projects that have ended up costing at least three times what they were supposed to, and nearly always failed to deliver the standards of service that were promised. Nobody has quite worked out why the rebuilding of Wembley Stadium took so long to get going, why it will take forever to complete or why the price is so high when compared to other stadiums built privately by several Premiership football clubs.

Repeated financial disasters always seem to occur when the government tries to install a new computer system in any of its agencies. The Inland Revenue is a case in point, as is the computer upgrade that recently took place at the spy centre GCHQ: an original estimate of £20 million (€29 million) has become a final bill of £450 million. If the financial track record of other countries is so poor, the chances of a British Olympic games ever turning a shilling do seem remote. But the question of just why we are so bad at such projects always remains. We know we are hopeless but nobody seems able to figure out why we get it so wrong.

If Paris gets the games, I am willing to wager that they will be magnificent, no expense will be spared and no Frenchman will ever pay attention to the full cost, if it is ever revealed.

The obvious comparison is the different experience that France and Britain have had with building the rail link between Paris and London.

British and French banks have lost billions, shareholders on both sides of the Channel have been wiped out, yet the French side of the link was finished a long time ago. The British part of the project might, if we are lucky, be completed by 2012.

Yet nobody in France is that bothered by the financial consequences; great pride is taken in having simply built something (and having beaten the Brits by years).

I think the answer to the puzzle lies as much with perception as it does reality. That the French, and many other countries, seem to be so much better at the game lies as much with cultural attitudes as it does with a uniquely British failing. Other countries are probably just as financially incompetent as us at building things but they have a different attitude towards costs.

We look at the accounts and despair, but others just shrug: whatever the price, it is one worth paying. There is a belief that the benefits of grand, publicly funded designs are difficult to measure and cannot be captured in a traditional accounting sense. The still hopelessly audited EU itself is perhaps the prime example.

All of the available evidence points to the simple fact that the public sector simply cannot make a decent financial fist of big projects of any kind. This sounds like a statement with huge ideological undertones but it is merely an observation based on a mountain of evidence.

If it is obvious to Tony Blair why the Olympics should come to London, he should explain why. Merely stating that it will be "good for London and the UK" may be blindingly obvious to some but the Prime Minister needs to explain with a touch more precision just what he means.