The failure of G4S to provide the required number of security staff for the London 2012 Olympics has undermined confidence in Games organisers, said a committee of MPs.

As a result of the security company's shortfalls, the Government has had to draft in an extra 3,500 soldiers to cover the sporting event.

On Tuesday G4S chief executive Nick Buckles told the Commons Home Affairs Select Committee the debacle was a "humiliating shambles for the company" and the firm's reputation was now in tatters.

The committee chairman, Margaret Hodge, has also criticised the Department for Culture, Media and Sport (DCMS) for a lack of transparency over finances.

"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." Hodge said.

The committee's report also explains that there has been no overall figure about how much the Games will cost the taxpayer.

There is a public sector funding package of £9.3 billion but there is other Games-related expenditure - such as funding of elite athletes - which has also come from the public purse.