Heathrow Airport will be shut all day after an "unusual and unprecedented" fire hit a nearby substation. Officials are scrambling to identify the cause of the blaze - with thousands of people hit by flight cancellations.
Heathrow says it hopes to run 'full operation' tomorrow.
Counter-terrorism police are leading the investigation into the fire at the substation that knocked out the power to the airport, but the Met Police says there's currently no indication of foul play