MPs have said the private company behind the London 2012 security shambles should be the first firm put on a Government blacklist of high-risk businesses that have failed to deliver.

Politicians also repeated their demands for G4S to give up its £57m management fee, saying it should pay the people it trained but failed to use because of its failings.

A damning Home Affairs Select Committee report blames G4S for the debacle, which saw thousands of troops brought in at the last minute to help keep the Games secure.

The report exonerates Olympic organisers Locog and the Home Office, saying the fault lies "firmly and solely" with the security firm.

The company, which has already taken a £50m loss on the Games, must now "look to the bigger picture, and its long-standing relationship with its biggest client in the UK: the taxpayer", the committee's report said.

"By waiving the £57m management fee in its entirety, a small fraction of the £759m that it receives from the British taxpayer every year, G4S would send a strong signal to the public that it is serious about offering fair and reasonable redress when things go badly wrong."

The move would help draw a line under its failure, it added.