London-Heathrow will be closed for ALL of Friday due to a “significant power outage” caused by a fire in an electrical substation.

There are currently 120 aircraft in the air that will be diverting to alternate airports or returning to their origins. https://t.co/TEHf2kJO23 pic.twitter.com/Lot0lsJLz8

— Flightradar24 (@flightradar24) March 21, 2025