The Chief Executive of G4S has said the company stands to lose up to £50m of its £284m contract to supply security staff to the London Olympics.

Speaking on the Today programme, Nick Buckles said: "We accept that we underestimated the task of supplying staff for the Olympics. We deeply regret that."

Mr Buckles told Today presenter Justin Webb that the company is recruiting a large number of people. "They are all working through a process of interview, two or three different degrees of training, licensing, accreditation."

Mr Buckles added that 100,000 people had applied for interview and the number of people interviewed by the company was 50,000.

"So, basically, you work through that process of numbers," he explained, "and as they were getting ready for deployment over a period of time, it's only when you get closer and closer to the games that you realise that the number isn't as high as you expect."

And Mr Buckles admitted: "I can't say categorically that all the guards recruited by G4S for the Olympics are able to speak fluent English".

The Ministry of Defence says it will be supplying 3,500 additional troops to make up the shortfall in security staff during the Games.

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