Officials said there was no suggestion of foul play, but the cause is still under investigation. The fire brigade said its investigation would focus on the electrical distribution equipment at the substation.
Even so, London’s Metropolitan Police Service said counterterrorism detectives were leading the investigation because of the fire’s impact on critical national infrastructure.
Energy Secretary Ed Miliband said it was “an unprecedented event.”
“Obviously, with any incident like this we will want to understand why it happened and what if any lessons it has for our infrastructure,” he told Sky News.
The airport said it had made space for extra flights, but it is expected to take days to get stranded passengers to their destinations and displaced aircraft into the proper locations.
apnews.com