It also compared the 468 million pound rise to what it said was an increase of 3.3 billion pounds over the last year of the previous, Labour government in 2009/10.

“There will always be factors over which the (MoD) has limited control, but it must do more to learn from previous projects .... the Department has more to do to address its long-standing issues on project performance,” said Amyas Morse, the head of the National Audit Office (NAO).

The office conceded that fuel price inflation of 336 million pounds over the past year in the strategic tanker programme - a project to lease refuelling aircraft - w a s not the fault of the MoD, and said cost overruns and delays were to be expected in technically challenging projects such as the aircraft carriers.

Defence Secretary Philip Hammond said the government had “taken the tough decisions necessary to get the equipment plan under control”.

“Fuel inflation and other factors outside of the department’s control are responsible for three-quarters of the cost increase over the past year,” he said.

The EADS-led AirTanker consortium behind the tanker aircraft said rising fuel prices were not an intrinsic part of the project and should not have a bearing on assessments of programme delivery.