A passenger at London’s Heathrow airport. (Reuters)

London, Aug. 13 (Reuters): British Airways resumed more than 80 per cent of its scheduled flights from London’s Heathrow Airport on Saturday as staff struggled to clear the backlog from a wildcat strike during the peak summer holiday season.

A spokeswoman warned it would take several days to resume normal service, however, after the two-day strike grounded more than 110,000 passengers. Some flights resumed late yesterday after being cancelled since Thursday but thousands of passengers remained stranded at the airport.

Marquees were erected outside two of the terminals to provide refreshments and somewhere to sleep while a spokesman for the London Ambulance Service said it had treated several people for exhaustion, stress and dehydration.

Mike Street, the airline’s director of customer services and operations, said BA also faced a complex logistical challenge, with at least 100 aircraft and 1,000 flying crew in the wrong place.

“We are working as hard as we can to get customers away on their holidays,” he said.

A spokesman for the airline said 85 per cent of short-haul flights, some 170 departures, and 80 per cent of long-haul or 60 flights were scheduled to leave Heathrow today.

“We now have visible signs of people moving through the airport and getting on planes and we’re hoping to continue that,” he said.

Around 1,000 BA staff walked out on Thursday in support of workers who were sacked at the company’s catering supplier, Gate Gourmet. More than 700 flights have since been cancelled.

“We apologise unreservedly to our customers,” BA said on its website. “This is an unprecedented situation.”

The airline said only customers with confirmed reservations would be accepted into the airport for travel.