The “chaos” surrounding the Olympic security staffing contract with G4S was “predictable,” according to the government’s Public Accounts Committee.

In its report ‘Preparations for the London 2012 Olympic and Paralympic Games,’ the committee was critical of the inaccuracy in workforce planning that led to a hike in the total security presence required from 10,000 to over 23,000 in just over a year.

The increase in people requirements led to costs nearly doubling costs from £282 million in 2010 to £553 million in 2011.

Committee members were “not convinced” by the government’s response that “it was not possible to produce final costs before the detailed venue plans and competition schedules were drawn up.”

LOCOG’s management of the G4S contract also came under scrutiny, as the committee questioned why it had entered into a contract based on earlier estimates of guard numbers and then had to renegotiate the contract terms within a year.

“[It] does not give us confidence in the management of this aspect of the preparations for the Games,” the PAC report said.

“Accountability for monitoring security arrangements is unclear and there is insufficient challenge for service providers. Further, the rise in programme management and operational costs over the year - more than twelve fold from £10 million to £125 million - has yet to be convincingly justified to us.”

The committee also questioned whether G4S should pocket public money when it had failed to deliver the contracted number of guards. “Value for taxpayers’ money demands that G4S not only pays for all additional costs incurred by the government, but also incurs financial penalties for the failure to deliver. We will return to this matter as a priority after the Games,” the report concluded.

Margaret Hodge MP, PAC chair, said: “The chaos which has emerged over the security contract was predictable and undermines confidence in those responsible for managing the Games. There is now a last minute scramble to make sure there will be enough security personnel on the ground. In evidence to us before Christmas, all those concerned gave assurances that the contract could be met despite more than doubling the number of guards before the ink was dry on the original contract.

“No credible explanation has been given for an astonishing twelve-fold hike in management costs, from £10 million to £125 million, and G4S still has not been able to deliver. Now troops are having to be drafted in. The Home Office needs to get a grip on LOCOG and G4S urgently.”