The official told a parliamentary committee that he had raised concerns about the resilience of Heathrow’s electricity supply just days before a fire forced the airport to shut down.

Heathrow was thrown into darkness on April 20 after a fire at the nearby electrical substation cut off its power supply.

London's Heathrow Airport​, one of the busiest airports in the world, was shut down by a power outage caused by a fire at an electrical substation.

Trains linking Paddington Station with Heathrow’s Terminal 5 may be canceled or face delays of up to 30 minutes.

The boss of Heathrow Airport has apologised to the over 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".

Heathrow’s boss will be questioned by MPs on Wednesday about the airport’s closure for most of a day last month. Chief executive Thomas Woldbye will give evidence to the Transport Select Committee as part of its investigation into the shutdown on March 21,