London 2012: Theresa May still can't say how many guards G4S will provide for the Games G4S only told the Government that they would be unable to meet their contractual arrangements last Wednesday and we took immediate action. Asked why the 20,000 accredited guards could not be employed, Mrs May said: "I think there are a number of things. The first is about the scheduling problems G4S themselves have had. And there will be individuals who are now saying they do not wish to take that work up - that may be for a number of reasons. A spokesman for G4S admitted that police officers from nine forces had been called on to fill in for missing security guards. The spokesman added: "This situation is being rectified over the coming days, which should lead to the withdrawal of police officers from those roles assigned to private security." The forces involved are Dorset, Surrey, Hertfordshire, Northumbria, South Wales, Strathclyde, West Midlands, Thames Valley and Greater Manchester. It emerged yesterday that ministers had been warned 10 months ago in a confidential report by HM Inspectorate of Constabulary about concerns over G4S's capacity to supply the Games with sufficient personnel. It was following the HMIC report that a review of security requirements led Locog to increase the number of security guards to be supplied by G4S from 2,000 to 10,400 while the value of the contract more than trebled from £86 million to £284 million. Nick Buckles, the chief executive of G4S, is due to appear before the Commons Home Affairs Committee tomorrow. He has already conceded he may be forced to quit over the debacle, which has seen the firm's share price fall by 10 per cent.