The Heathrow shutdown has sparked travel chaos around the world, with tens of thousands of passengers left stranded at airports abroad and dozens of planes from the US, the Caribbean and India turned around in mid-air. 

As one of the world's busiest airports handling around 1,300 landings and take-offs each day, disruption caused by its closure after a fire at a nearby electricity substation has quickly spread around the globe. 

When Heathrow shut at around 3am, 120 flights were already on their way there, according to Flightradar24. Out of these, 36 were still in the air four hours later as pilots - mainly flying from Asia - scrambled to work out where they could land. 

Passengers from as far away as San Francisco, Japan and Perth in Australia were caught in the carnage, with data firm Cirium estimating that 290,000 people who were scheduled to fly to or from the airport will be affected by the closure.

BBC weather presenter Simon King revealed his mother had been flying to the UK from Jamaica when her plane was forced to turn around in mid-air because no British airport could take it - with an astonishing radar image revealing the manoeuvre. 

Meanwhile, one British woman stuck in China with her husband said she had 'no idea' about how they would get home after their flight was cancelled.  

'We should have taken off at 1pm local time here Instead we are stuck at the airport with no idea how and when we will get home!' she told MailOnline. 

'We can't check in to a hotel because of the strict immigration visa policy, to enter back in to the airport, we need a boarding pass so customs can confirm when we are leaving the country.'

Passengers on other flights departing from the United States will instead touch down at other airports across the nation. One flight from Dallas will travel to Bangor, Maine instead of London, while a flight from San Francisco will land at Dulles International. 

Flight US 146 from Newark was among one of the first flights impacted by the diversion while already in the air. It is now set to land in Shannon in Ireland shortly after 5am. It was scheduled to land at Heathrow at 5.55am. 

Meanwhile the QF9 Qantas flight from Perth to Heathrow has been diverted to Paris as European airports prepare for an influx of planes that are too far into their journeys to turn back. 

Amsterdam, Newfoundland in Canada and Helsinki are among some of the cities accepting diverted flights.

Weary passengers at airports across the globe are eagerly awaiting news from their airlines.

One traveler who is waiting in a Toronto terminal said his flight bound for Heathrow still says it is taking off as scheduled in 50 minutes.

'They don't have the heart to tell us,' he wrote on X.

Another traveler, whose plane from JFK took off two hours ago, told DailyMail.com she had been circling the skies of New York since they departed.

She said pilots gave a single announcement 'about 40 minutes after we took off saying the airport was shut. 

'[The pilot said] we have to circle to dump fuel before landing back at JFK, but didn't say for how long or if we'd get another flight.' 

On a flight from Japan, travelers who have been in the air for 13 hours will find themselves in Helsinki rather than London as planned. 

Other long haul flights which were diverted include a British Airways flight from Doha now arriving in Frankfurt, and another which departed from Nairobi and will land in Manchester. 

Some lucky passengers have been diverted to other London Airports. British Airways flights from Johannesberg, Lagos and Cape Town will now touch down at Gatwick.

Travelers from Paris, Frankfurt, Berlin, Houston, Hamberg, Zurich, Dublin and Barcelona are among scores who will wake to learn their flights have been canceled. 

The blaze broke out at 8pm on Thursday and the busy airport, which sees a plane land or take off around every 45 seconds on average, announced its closure six hours later. 

FlightRadar24 spokesman Ian Petchenik said that the unplanned closure of Heathrow  will be felt by airlines and travelers all over the world.

'Heathrow is one of the major hubs of the world,' he told the Telegraph. 'This is going to disrupt airlines' operations around the world.'

A Heathrow Airport spokesperson said: '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.

'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.

'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.'

Footage of the blaze revealed large clouds of smoke billowing into the sky as firefighters worked tirelessly to extinguish it.

Meanwhile videos from inside Heathrow showed the airport lying largely dark amid the power outage. 

Assistant Commissioner of the London Fire Brigade Pat Goulbourne said: 'This is a highly visible and significant incident, and our firefighters are working tirelessly in challenging conditions to bring the fire under control as swiftly as possible.

'The fire has caused a power outage affecting a large number of homes and local businesses, and we are working closely with our partners to minimise disruption. 

'Firefighters have led 29 people to safety from neighbouring properties, and as a precaution, a 200-metre cordon has been established, with around 150 people evacuated.

'Due to the significant amount of smoke, we strongly advise local residents to keep their windows and doors closed.

'This will be a prolonged incident, with crews remaining on scene throughout the night. As we head into the morning, disruption is expected to increase, and we urge people to avoid the area wherever possible.'

The cause of the fire remains unknown.  No injuries have so far been reported.