Ed Miliband described the fire at a sub-station near Heathrow Airport as “catastrophic” and “unprecedented” this morning.
Heathrow, one of the world’s busiest airports, will remain closed on Friday after a fire erupted overnight at a nearby power station.
At least 1,300 flights are expected to be cancelled across the day.
Passengers have been urged to stay away, and trains to Heathrow have been suspended.
Speaking to broadcasters on Friday morning, the energy secretary revealed that the incident was especially severe because a back-up generator was also affected by the blaze which erupted overnight.
Heathrow is one of the world’s busiest airports and has a plane landing or taking off around every 45 seconds – meaning its closure will affect flights over the next coming days.
Miliband told Sky News: “I’ve spoken to the National Grid about what’s happened, which is a catastrophic fire at a sub-station that serves Heathrow.”
He said that “it’s too early” to know the cause of the fire, adding: “The main priority at the moment is to get the fire out.”
The cabinet minister said that 100,000 people were also out of power overnight but it’s this number has ow been reduced to 4,000 after the National Grid re-routed electricity supplies.
He continued: “My heart goes out to all of the people impacted by this, people flying into Heathrow, flying out of Heathrow.”
The energy secretary said that the National Grid had told him a back-up generator was also affected by the fire, “which gives a sense as to how unusual and how unprecedented it was”.
“There is a second backup they are seeking to use to restore power,” Miliband said.
“There are back-up mechanisms in place, but given the scale of the fire, the back-ups also seem to be affected.
“With any incident like this, we will want to understand why it happened and what if any lessons it has for our infrastructure.”
However, when asked what this means about the country’s “critical infrastructure,” Miliband said he was “reticent” to draw any conclusions just yet.
The minister also did not confirm if the government would be holding an emergency COBRA meeting, although he told LBC there was no indication of “foul play”.
He told Sky News: “I’m sure the government will be convening in the most appropriate way.
“I’m not going to anticipate the precise form of that, but I’m already in touch with my colleagues on this issue.
“As I say, I’ve spoken to the National Grid, who are really at the epicentre of this, and we will be doing everything we can, both to restore power and help the National Grid.
“To do that, and to ensure that the DfT (Department for Transport), and the government as a whole, plays its part in, as best we can, minimising the disruption to passengers.”