The chairman of the Home Affairs Committee, Keith Vaz, has said the problems that had arisen raise questions as to whether the staff G4S had managed to recruit were up to the job.
He told BBC News:
We do need to examine what is the workforce that is in place at the moment. Have they been properly trained?
Are they going to be able to communicate with those that arrive at the Games and are they qualified to do what they are supposed to do?
I hope this is an opportunity for Mr Buckles on Tuesday to come out with the facts, to be very clear, to be very open, to be very transparent with Parliament so that we can get to the bottom of what has happened."
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Guillier conceded a "severe defeat" defeat to his supporters as the result came in.
The outage struck Hartfield-Jackson Atlanta International Airport at around 1pm local time, stopping all outgoing flights.
It will be a chilly day for many parts with the highest temperatures, about 10 Celsius (50F) in the far northwest.