Footage shows the scene inside Heathrow Airport in the early hours of Friday morning after a fire plunged the building into darkness.

Officials confirmed the airport - the biggest airport in the UK - would be closed for at least 24 hours due to an explosion at an electrical substation.

The airport said: 'Due to a fire at an electrical substation supplying the airport, Heathrow is experiencing a significant power outage. To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23h59 on 21 March.

Heathrow is experiencing a significant power outage across the airport due to a large fire at a nearby electrical substation. Whilst fire crews are responding to the incident, we do not have clarity on when power may be reliably restored.

'We expect significant disruption over the coming days and passengers should not travel to the airport under any circumstances until the airport reopens.

'We will provide an update when more information on the resumption of operations is available. We know this will be disappointing for passengers and we want to reassure that we are working as hard as possible to resolve the situation.'

Hundreds of departing flights at the London airport are expected to be cancelled, and those arriving will be delayed or diverted.

Heathrow was the world's second-busiest international airport in 2024 behind Dubai, according to travel data firm OAG.

The London Fire Brigade said its crews were tackling the fire in Hayes in west London and had evacuated around 150 people as a precaution.