The boss of Heathrow Airport has apologised to the more than 200,000 passengers whose journeys were disrupted by its closure last month following a fire.

Thomas Woldbye offered his “deepest regrets” adding that the “situation was unprecedented”.

Speaking to MPs, he said he recognised “the considerable inconvenience and concern it caused”.

The airport was shut down for more than a day in March after a fire at a nearby electrical substation.

Mr Woldbye said Heathrow realised “during the early hours” of Friday 21 March that “we were losing power to the airport”.

“In the operations centre red lights were going and systems were powering down,” he said. “We had no idea why.”

“We then had a slightly later stage call from the fire department that that substation was on fire,” he said.

Heathrow is supplied by three substations, but knocking out one caused loss of power to the airport.