LONDON, ENGLAND - JULY 18: Members of security staff and soldiers check vehicles as they enter the Olympic Park site on July 18, 2012 in London, England. A failure by the security firm G4S to provide their contracted number of security staff to guard Olympic venues has resulted in 3500 extra troops and additional police officers being deployed to meet the shortfall. (Photo by Oli Scarff/Getty Images)
LONDON, ENGLAND - JULY 18: Members of security staff and soldiers check vehicles as they enter the Olympic Park site on July 18, 2012 in London, England. A failure by the security firm G4S to provide their contracted number of security staff to guard Olympic venues has resulted in 3500 extra troops and additional police officers being deployed to meet the shortfall. (Photo by Oli Scarff/Getty Images)