Home Secretary Theresa May has denied that Olympics security is a shambles after the military was called in to plug a gap left by the failure of private provider G4S.
With just two weeks to go until the opening ceremony, an extra 3,500 servicemen and women are being flown in after G4S said it might not be able to provide enough guards for all the venues.
With more than £100 million wiped off the firm's market value and MPs accusing the company of letting the country down, Mrs May insisted ministers were only told of the "absolute gap in the numbers" on Wednesday.
In its hour of need, the Government turned to the troops, many of whom have recently served in Afghanistan and are facing cuts in the biggest re-structuring of the service for decades, to help keep the Olympics safe and secure for up to 10 million spectators.
Warning orders started going out to troops at the weekend, putting them on shortened notice to move.
But Mrs May denied it was a "shambles" and insisted there is "no question of Olympic security being compromised".
Asked whether there would be any financial penalties for G4S on its £284 million contract, Mrs May said the firm's deal was with organisers Locog, but she understood that penalty clauses were included.
A total of 17,000 servicemen and women will now be involved in the Olympics, including 11,800 soldiers, 2,600 sailors and marines, and 2,600 airmen. Some 11,000 of these will be involved in the security of more than 30 sporting venues and some 70 non-competition venues, including car parks and hotels, while others will carry out specialist support roles including air security, search teams, communications and logistics, among others.
Overall, a 23,700-strong security force for the Games will include a mix of military, private security guards and at least 3,000 unpaid London 2012 volunteers.
Defence Secretary Philip Hammond acknowledged the extra burden on military families, but said bringing in extra resources was "prudent" and insisted the deployment "will have no adverse impact on other operations".