Heathrow expects to handle around 80 percent of all overseas travellers to the London Games and, although athletes and officials are set to arrive in manageable numbers over several days, most will depart in one fell swoop.

To cope with the mass exodus of 10,000 competing athletes and their 38,000 bags in the three days following the closing ceremony on August 12, a "pop-up" terminal has been erected on a car park between Heathrow's Terminals Four and Five.

The temporary terminal, soon to be fitted with 31 check-in desks, seven security lanes, bag-drop facilities and toilets, will be finished by late June, ready for its three days of operation between August 13 and 15.

On the next day workers will start pulling down the structure. "We considered lots of different options, but this site is currently intended to return to a car park," Nick Cole, head of Olympic and Paralympic planning for Heathrow, told Reuters

The terminal will be staffed by up to 50 full-time workers and 1,000 meet-and-greet volunteers.

The airport estimates it will take 30 minutes for athletes to pass through the temporary terminal before buses take them to departure lounges.

It will encourage athletes and team officials to check-in at the Olympic Village in east London the night before their departure to further relieve pressure at the airport.

Heathrow's operator BAA, majority owned by Spanish infrastructure group Ferrovial, says its Olympics operations - which include remote check-in facilities at the Olympic Village - will together cost 20 million pounds to implement.

Heathrow, which runs at 99-percent of its capacity on an average day, estimates every single seat on every aircraft will be full on August 13, something the airport has never seen before.

The airport is planning for 137,800 departures and 203,000 bags - many of them oversized - making it the busiest day in the airport's history.

"To give you an idea of scale, our busiest day ever saw 123,000 departures. And in terms of bags, our busiest day to date has been 150,000 bags," Cole said.

(Editing by Tim Castle)

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