Footage shows a fire raging close to Heathrow Airport in the early hours of Friday morning - as the building was plunged into darkness and forcing hundreds of flights to be cancelled.

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 blaze is believed to have started at a vital part of the grid on Nestles Avenue in Hayes, West London. Thousands of homes were also affected.

Two British passengers who were mid-air on a Boeing 777 when they discovered the delay said they were due to land at 6 pm at Heathrow but are now facing uncertainty.

Using the plane's onboard Wi-Fi, Andrew, from Bristol, Somerset, said: 'Our Etihad flight from Bangkok to London is via Doha. Nobody knows what is going to happen.

'We could be stuck for a while in the Middle East. We will certainly be looking at a very long delay.'

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.

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.'