The phrase “an inconvenient truth” may have been used for Al Gore’s film on global warming, but it also serves pretty well to describe the cost of building the London Olympics.

After months of steady inflation we now have a headline figure of £9.3bn to build the park, regenerate Stratford, cover VAT and put aside a £2.7bn contingency fund. But rather than setting a clear cost framework that anyone who cares to look at can understand, the closer you examine this “final” figure, the more vague and cryptic it appears to be.

The good news, of course, is that the budget looks a lot more realistic than the initial estimates, which were based on 2000 figures and didn’t take account of regeneration spending. When you come to the bit that deals with the construction of the Olympic park, that seems to have risen £700m. Now, given the extremely complicated nature of ground conditions and the runaway price inflation we’re experiencing, many construction observers suspect that that cost estimate is on the light side.

Most industry experts are warning that the apparently generous contingency fund will not be enough to cover whatever the out-turn cost eventually proves to be – and that the money shouldn’t have been announced as a contingency but part of the budget. It is, of course, more palatable to politicians to suggest that the Olympics will cost nearly £3bn less than it probably will, but is anyone really buying that? The bad news for the industry is that if the project eats through the contingency money, the public perception will be that it can’t keep costs under control, when in reality it had its sums right all along.

But it’s not just the contingency that’s hard to fathom. The more one tries to scrutinise this budget, the more illogical it seems. For one thing, there is provision for “extra” security when there doesn’t seem to be any for basic arrangements. And the danger is that the Olympic Development Authority (ODA) and CLM will appear responsible for this, and things like the delivery of community sports facilities, because they’ve all been put in the same pot. So if the budget does go up again, they’ll be the likely scapegoats.

Anyone brave enough to take the chair of the ODA might want to carry out their own due diligence and work out what precisely the ODA has to pay for. This is, as we’ve said before, a fantastic opportunity for London and the industry to show what it’s made of. The last thing we need is to kill its morale with a thousand budget provisions. This announcement ought to have been the end of the story. The inconvenient truth is that it’s probably not.

Denise Chevin, editor