London’s Heathrow airport has been closed until midnight on Friday after a fire at an electrical substation supplying the airport caused a “significant power outage” and left thousands of homes without power. In a statement on its website and shared on social media, Heathrow airport said all passengers were advised not to travel to the airport. “To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23h59 on 21 March,” the statement said. The fire at an electrical substation in west London has left more than 16,000 homes without power, and forced more than 100 people