In addition to the 5, 000 personnel allocated to that role, some 3, 500 would provide venue security.

BBC: London 2012: 13,500 troops to provide Olympic security

"The problem for G4S has been in allocating personnel through their scheduling programme to particular venue security tasks, " she explained.

BBC: May: Exact size of Olympics staffing shortfall is unclear

The guards employed by G4S will be responsible chiefly for such tasks as providing venue perimeter security, a spokesman for the contractor said.

CNN: London's Olympic security headache