Two weeks before the start of the London Olympics, the British government is defending its security plans after having to call in 3500 military personnel to protect venues.
The Government was forced to act because a contractor failed to supply enough trained security staff.
The troops are in addition to 7,500 military personnel already agreed for venue security, the BBC reports.
British Home Secretary Theresa May said it was discovered only on Wednesday - 16 days before the Games begin - that contractor G4S did not have enough trained security staff.
In response to questions about safety during the event, Mrs May told the House of Commons there was "no question" of Olympics security being compromised.
"I can confirm to the House that there remains no specific security threat to the Games and the threat level remains unchanged. "
G4S was contracted by the London 2012 Organising Committee to supply 10,400 of the 23,700 security staff needed for the Games.
It said it had 4,000 people already working and a further 9,000 people going through the final stages of extensive training, vetting and accreditation.
It is understood that it was training more people than their contract required to make up for any shortfall in staff taking up their posts.
The company said there had been delays in moving applicants through the final stages.
Transport planners are also looking at alternative routes into London after the motorway between Heathrow Airport and the city was closed for emergency repairs.