The government does not yet know exactly how many security guards will be provided for the Olympic Games by private firm G4S, Home Secretary Theresa May has said.
As Mrs May took an urgent question tabled by shadow home secretary Yvette Cooper on security arrangements for the Olympics on 16 July 2012, she assured MPs: "This government is on course to deliver a safe and secure games that everybody will enjoy."
Mrs May insisted she first became aware of the problem when G4S admitted it would not be able to fulfil its contractual obligations to games organisers Locog last week, prompting the government to deploy 3,500 troops to make up the numbers.
But in response to a question from Labour MP Nick Smith, the home secretary made it clear that the exact size of the staffing shortfall was still unclear.
"The precise balance of the numbers that they will be providing will become clear over the next few days," she told MPs.
G4S had "repeatedly assured us they would overshoot their targets", until last Wednesday's acknowledgement of the problem, Mrs May said.
But Ms Cooper told MPs Tory London Mayor Boris Johnson had said the problems were known about "ages ago" and his deputy Stephen Greenhalgh had claimed security concerns had been raised "repeatedly".
"How on earth could the minister responsible for delivering Olympic security be the only person who didn't know?" she asked.
Mrs May pointed out that more than enough staff had been accredited to work at the games.
"The problem for G4S has been in allocating personnel through their scheduling programme to particular venue security tasks," she explained.