A flight radar video shows the dramatic moment hundreds of planes turn around after discovering had been shut down by a huge fire.

Many thousands of passengers have been hit with flight cancellations today after the blaze at a nearby substation knocked out power to Britain's busiest airport, . Around 1,350 flights to and from the airport are , and passengers have been ordered . The airport said it expects "significant disruption" to last into the weekend. Now, one video shared by aircraft tracking service Flightradar24 shows planes heading towards Heathrow from across Europe and the Atlantic being forced to reroute upon being told of the closure.

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Some 120 flights were in the air when the closure was announced early on Friday. Many were turned around and others diverted to Gatwick Airport, Charles de Gaulle Airport in Paris or Ireland's Shannon Airport.

The London Fire Brigade confirmed later this morning that the fire at North Hyde substation in Hayes was "under control", adding that a transformer device had been the cause of the blaze and 70 firefighters "worked tirelessly" to tackle it.

Energy Secretary meanwhile said the country "have to look hard" at "resilience" for major institutions such as the airport in the wake of the "catastrophic fire". He told Radio 4's Today programme: "I spoke to the National Grid this morning.

"There's obviously been a catastrophic fire at this substation, an unprecedented event actually in their experience.

It appears to have knocked out a back-up generator as well as the substation itself.

"What I know is that they are working as hard as they can to restore power as well as the fire being put out.

"It's too early to say what caused this but I think obviously we will have to look hard at the causes and also the protection and the resilience that is in place for major institutions like Heathrow. With any event like this we'll have to both understand its causes and learn lessons from it."

Heathrow bosses said in a statement that they will provide an update on the airport's reopening when it has more information on when power will be restored.

"To maintain the safety of our passengers and colleagues, we have no choice but to close Heathrow" for the full day, the airport said. "We expect significant disruption over the coming days, and passengers should not travel to the airport under any circumstances until the airport reopens."