London 2012: Pressure mounting on G4S boss Nick Buckles

Pressure is mounting on the chief executive of G4S after he apologised for failing to recruit enough security staff for the London Olympics.

Nick Buckles said he had become aware of the situation only "eight or nine days ago".

He is due to appear before the Home Affairs Select Committee on Tuesday to answers MPs' questions.

The Home Office said issues raised by inspectors about security last year were dealt with by February.

It emerged last Wednesday that 3,500 troops were being drafted in to plug the gaps in security staff provision.

Mr Buckles told the BBC that problems with G4S's recruitment and deployment of Games security staff had only recently been identified.

"I began to know it was going wrong eight or nine days ago," he said.

"Basically we are recruiting a large number of people and they are all working through a process of interview, two or three different degrees of training, licensing and accreditation.

"It is only when you get closer to the Games, you realise that the number is not as high as you expect."

Mr Buckles indicated in an interview with the Sunday Telegraph that he "could quit" over the fiasco.

"I have got to make sure we deliver this contract. What happens thereafter is down to others. It's a big setback for us, we are really disappointed with how this has turned out.

"I want to stay. I have been here 27 years, I am very committed to staying. It just depends, doesn't it?"

Theresa May said she only found out G4S couldn't deliver the goods last Wednesday. The firm's chief executive said he discovered how bad things were nine days ago. So there were six days when he knew but the home secretary didn't.

That's despite daily meetings between the security firm, the Home Office and Locog, the committee charged with making the Games happen.

The BBC's been told senior level meetings, to discuss security, have been taking place for three weeks. The minister with responsibility, James Brokenshire, has been attending. G4S told the BBC it had always given Home Office officials and ministers "total visibility" about what it was doing, as part of a "transparent process".

Yet the home secretary, and presumably her minister James Brokenshire, didn't know about the failure to recruit until Wednesday.

At the start of last week, Mrs May told Parliament she was confident their partners would deliver.

Labour is urging her to update the Commons saying there are serious questions about the level of oversight. One party source said if ministers were relying solely on what G4S were telling them then that was "just being a patsy".

Asked if he had considered resigning, Mr Buckles said "of course".

G4S will lose between £30m and £50m on the contract, which is worth a total of about £280m.

The Commons Public Accounts Committee has summoned G4S, two government departments and Games organiser Locog to answer questions in September.

The Home Office said that, contrary to some reports suggesting HM Inspectorate of Constabulary warned ministers over problems with G4S's ability to provide security for the Games, the HMIC had not investigated G4S.

A Home Office spokesman said: "We asked HMIC to carry out a number of inspections to test that Locog security planning was on track.

"While an early inspection highlighted issues to be addressed, a report in February 2012 said that Locog was on track to deliver the required number of security personnel."

The HMIC report went to ministers in September. At the time G4S was contracted to hire 2,000 security guards for the Games - increased to 10,000 following a security review in December.

Home Secretary Theresa May has said she was made aware of the scale of the problem at G4S only last Wednesday.

This is despite the BBC being told there have been senior level meetings every day for the past three weeks involving Home Office officials, G4S and Locog.

Security minister James Brokenshire has been at those meetings, according to BBC political correspondent Robin Brant.

Labour has urged the home secretary to come to Parliament to update MPs, and that could happen as early as Monday, our correspondent says.

One Labour source said if ministers were relying solely on what G4S was telling them they were "just being patsies," he added.

Shadow minister Dame Tessa Jowell said the "integrity and resilience" of the security plan must be established.

Clint Elliott, chief executive of the National Association of Retired Police Officers (Narpo), said: "It is astonishing that G4S can't have recruited these people in a time of high unemployment and at a time when many police officers are being forced to retire early and are actively looking for work.

"What G4S tend to do is rely on the old boys' network and word of mouth to recruit people from our organisation - which is okay for small numbers but for 10,000 people you really need something a bit more substantial."

A G4s spokeswoman said the firm had not contacted Narpo but instead contacted retired officers whose details were on its own database.