As many as 1,350 flights were hit as Britain’s Heathrow Airport was closed all day on Friday after a fire at a nearby electrical substation knocked out its power, disrupting flights for hundreds of thousands of passengers at Europe’s busiest travel hub. After several hours, Heathrow Airport said it was safely able to begin some flights. The airport announced early on Friday it would be closed until 11.59 pm because of the fire. Around 2,00,000 passengers have been affected by the closure. Online flight tracking service Flightradar24 said more than 1,350 flights were scheduled to take off or land at Heathrow on Friday. Heathrow has also apologised for the inconvenience caused by the power outage.