A computer software failure caused the security fiasco at the Olympics, the Independent on Sunday has said, after talking to insider sources at security contractor G4S.

G4S defaulted on their Olympic security contract two weeks before the start of the games, meaning that 3500 members of the armed forces have been drafted in to provide basic security coverage for the Olympics. The security firm said they were unable to recruit and train enough guards to adequately police the site.

The Indy has suggested both that Home Secretary Therea May was aware of problems with G4S in September and that staff management software was to blame.

An insider said the root cause of the problem with G4S was its internal computer system which had failed to calculate staff rostering.

In a statement on the contract, G4S said:

We have recently encountered significant difficulties in processing applicants in sufficient numbers through the necessary training, vetting and accreditation procedures. As a result, we will be unable to deliver all of the necessary workforce numbers.

According to the Indy, the security firm offered to fulfill the contract at a price 25% less than that of competitors. ®