The chief executive of the G4S security group acknowledged Tuesday that his company's failure to live up to its Olympic obligations has turned into a nationwide humiliation.

Quizzed by a panel of angry British lawmakers over his company's failure to recruit enough people to guard the games, Nick Buckles gave a groveling mea culpa.

"It's a humiliating shambles for the country, isn't it?" asked Labour lawmaker David Winnick.

"I cannot disagree with you," Buckles said.

Buckles was hard-pressed to explain why his company had failed to inform officials until only two weeks before the start of the 2012 Olympic Games that its recruitment had failed -- forcing the government to call in 3,500 extra soldiers and police from various forces to fill the gaps.

G4S says it expects to lose between $54 million and $78 million on the contract, which is equal to about 12 percent of its annual profit.