Alistair Darling bowed to the credit pressures weighing on the London Olympics and agreed on Wednesday to bail out two of the biggest building schemes for the 2012 games, handing over a quarter of the £2bn ($2.7bn) set aside in contingency reserves to keep the project on track.

The chancellor agreed to release £394m from the contingency fund, while a further £67m is being taken out of a separate contingency pot set aside by the Olympic Delivery Authority, the body responsible for the games’ infrastructure.