The Olympic Delivery Authority has admitted that there is a 20% chance it will use more than its original contingency budget to build the venues for the 2012 Games.

The ODA says there is an 80% chance that the programme can be delivered for 拢7.1bn. This includes the 拢6.1bn budget and the agreed contingency of 拢968m, but not the additional 拢1bn that the government is reserving to cover 鈥渦nforeseen risk鈥�. If all this was used it would bring the total cost to 拢8bn.

The revelation, contained in the body鈥檚 annual report this week, comes as it emerged that CLM, the delivery consortium that includes Mace, Laing O鈥橰ourke and CH2M Hill, received 拢87.6m for its past year鈥檚 work.

Meanwhile, David Higgins, the ODA鈥檚 chief executive, will receive more than 拢500,000 for his work over the past year, including a 拢205,000 bonus. Howard Shiplee, the construction director, received 拢326,000, including a 拢52,000 bonus.

The ODA has so far spent 拢858m preparing for the Games. It said it had expected work worth 拢108m more to have been done by this date. It said the difference was owing to programme changes and cost savings on initial site works.