Heathrow Airport was warned about its power supply in the days before it closed because of an outage, MPs were told. Nigel Wicking, chief executive of Heathrow Airline Operators Committee, which represents airlines that use the west London airport, said there were a “couple of incidents” which made him concerned.

The airport was closed to all flights in the early hours of March 21 until about 6pm on the same day, after a power outage caused by a fire at a nearby electricity substation had started late the previous night. This disrupted more than 270,000 air passenger journeys.

Mr Wicking told the Transport Select Committee he spoke to the Team Heathrow director on March 15 about his concerns, and the chief operating officer and chief customer officer on March 19.

He said: “It was following a couple of incidents of, unfortunately, theft of wire and cable around some of the power supply that, on one of those occasions, took out the lights on the runway for a period of time.

“That obviously made me concerned and, as such, I raised the point I wanted to understand better the overall resilience of the airport.”

Mr Wicking said he believed Heathrow’s Terminal 5 could have been ready to receive repatriation flights by “late morning” on the day of the closure, and that “there was opportunity also to get flights out”.

Heathrow chief executive Thomas Woldbye said keeping the airport open during last month’s power outage would have been “disastrous”.

He told the Transport Select Committee: “It became quite clear we could not operate the airport safely quite early in this process, and that is why we closed the airport. If we had not done that, we would have had thousands of passengers stranded at the airport at high-risk to personal injury, gridlocked roads around the airport, because don’t forget 65,000 houses and other institutions were powered down.

“Traffic lights didn’t work, just to give you an example, many things didn’t work. Parts of the civil infrastructure didn’t work. So the risk of having literally tens of thousands of people stranded at the airport, where we have would have nowhere to put them, we could not process them, would have been a disastrous scenario.”

Asked by the Transport Select Committee if the closure of Heathrow would always have been part of the plan, Mr Woldbye said: “In the circumstances where we cannot secure the 100% safe operation of the airport, yes.”

Mr Woldbye also offered his apologies to the more than 200,000 passengers who saw their journeys disrupted by the closure. Speaking to MPs, he said he recognised "the considerable inconvenience and concern it caused", and offered his "deepest regrets" adding that the situation was unprecedented".