Out of London, and Heathrow Airport.

Has been shut down for 24 hours after a huge fire at a nearby electrical substation.

The closure at Europe's busiest airport is expected to cause ripple effects for passengers across the globe.

A fireball erupts into the darkness.

An electrical substation alight as more than 75 firefighters struggled to contain the flames.

Widespread power cuts hit the surrounding area.

Heathrow Airport within the impacted zone, only two and a half kilometers away from the fire.

Inside, it's usually bustling terminals, darkness.

And as morning broke, the skies above remained empty.

The airport releasing a statement, Heathrow is experiencing a significant power outage, and will be closed until 23:59 on the 21st of March.

Heathrow is one of the world's busiest airports with a plane landing or taking off around every 45 seconds.

The closure set to cause travel chaos for days.

It's a major hiccup, and really quite frankly, unforgivable.

A piece of infrastructure that important has to have a plan B.

Fire crews remaining at the substation throughout the night.

The London Fire Brigade saying a 200 meter cordon has been established with around 150 people evacuated.

This will be a prolonged incident.

In London, Hannah Sinclair, 9 News.

And Hannah Sinclair joins us now from Heathrow Airport.

Hannah, how have Australian travelers been impacted?

Good evening, Georgie, several Qantas flights have been impacted as a result of the all day shutdown here at Heathrow Airport.

A Singapore to London service and a Perth to London service have both been diverted to Paris with some of the passengers from those flights being told they'll be put on buses to get them here.

We spoke to one of them.

Take a look.

I'm on the flight tracker, the location changed to Paris, once we got on the ground, they told us that some buses would be picking us up in a couple hours.

There are another two Qantas flights scheduled to depart London today, which will also largely be impacted.

It's just after 7 o'clock in the morning here with travelers on this side of the world waking up to what is going to be a chaotic 24 hours of air trouble, Georgie.

Hannah Sinclair, thank you.