London’s Heathrow Airport has been brought to a complete standstill by a “significant power outage,” setting off waves of global travel chaos from one of the world’s busiest transit hubs.

The United Kingdom’s Heathrow airport has closed until midnight on Friday due to a power outage, throwing the plans of tens of thousands of travellers into chaos.

Heathrow Airport said it expected “significant disruption" over the coming days due to the power outage caused by the fire at a nearby electrical substation. The airport had previously said it would be shut until at least midnight local time, with no flights leaving today.