Don't expect the Olympic bill to stop at £9.3bn, warns organiser

John Armitt, chairman of the Olympic Delivery Authority (ODA), told MPs there was "no guarantee" the final total would be within the current £9.3billion budget.

This sum is already nearly four times the estimate that helped London win the bid in 2005.

MPs on the Commons culture, media and sport committee also teased out of Olympics chiefs that the number of major sponsors expected to support London 2012 had fallen from ten to seven.

The London Organising Commitfunnellingtee of the Olympic Games (LOCOG), whose chairman is gold medallist Lord Coe, was hoping to raise £650million from sponsors, including ten rated as "tier 1" investing more than £40million each.

But so far only three - sportswear company Adidas, energy firm EDF and Lloyds TSB bank - have signed up.

LOCOG plans to sign four more contracts.

During a 90-minute grilling, MPs expressed repeated concerns that the bill was going to soar beyond the £9.3billion set out by then Culture Secretary Tessa Jowell in March.

This includes a £2.2billion grab from the Lottery.

Mr Armitt, who took up his £250,000-a-year post in September, refused to rule out the possibility that the taxpayer could end up even more money to prop up the Games.

He said: "We are treating the budget as the absolute maximum we have and we have no intention of going over it. But if you say, 'Say you'll guarantee that' then no, I could not do that."

Mr Armitt hinted that the taxpayer would also be forced to make up any shortfall if revenue from a special National Lottery game set up to fund London 2012 dried up.

He added: "The funding that comes to the ODA comes from the Government. They would have to deal with that if it became an issue."

Lord Coe denied that Olympics chiefs were "falling into a trap" of preparing facilities which would stand empty after the Games finished.

He insisted venues including the 80,000- seat stadium in Stratford, East London - which will be reduced to a 25,000-seat track-and-field arena - an aquatic centre and velodrome would help regenerate one of the capital's poorest areas.

Last month, Olympics bosses were accused of incompetence by MPs appalled by the massive increase in the cost of the 2012 Games.

Olympics chiefs argue that the project is the most complex ever carried out in the UK in peacetime.