Heathrow Airport will be closed until midnight tonight (Friday, 21 March) after a large fire at a nearby electricity substation, disrupting travel for thousands of passengers.

Tracking site Flightradar24 estimates 1,357 flights would be affected (679 into and 678 out of Heathrow) today, (Friday, 21 March),  including around 120 which were already in the air this morning before the shutdown.

Energy Secretary Ed Miliband told Sky News it was too early to know what caused the "catastrophic fire".

Passengers have been warned to stay away from the airport and all trains to Heathrow have been suspended.

In a statement, Heathrow said: "To maintain the safety of our passengers and colleagues, we have no choice but to close Heathrow until 23h59 on 21 March 2025.

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

Planes usually begin landing and taking off at around 5am after the regular overnight quiet period.

Around 120 flights were bound for Heathrow when the airport announced it would be closing for the day.

Some will have turned back to the airport they departed from. But others were already crossing the Atlantic and have been diverted to airports in Europe.

British Airways said: "As a result, customers due to travel from Heathrow on Friday are advised not to travel to the airport until further notice.

"This will clearly have a significant impact on our operation and our customers and we're working quickly as possible to update them on their travel options for the next 24 hours and beyond."