The CEO of has warned that the cost of installing a more "resilient" power system to prevent a repeat of last week's outage could reach £1 billion, with airlines potentially footing the bill by upping their prices. Thomas Woldbye defended Heathrow's response after a fire at nearby a electrical substation in Hayes, which led to

He insisted that the airport in the early hours of last Friday for safety reasons, which impacted over 200,00 travellers. Mr Woldbye, who said he was asleep when the crisis hit, admitted that Heathrow should consider whether it could have acted more swiftly and reopened sooner. He told the that the airport will explore the possibility of installing a "fully resilient" power system, allowing it to switch between power sources. This might come at a cost of over £1 billion, if feasible.

Alternative solutions include purchasing additional generators to power more areas of the airport during outages. Currently, Heathrow's diesel generators only support critical operations like the control tower during power failures.

The substation , causing flights to divert to other airports while Heathrow took 24 hours to reopen.

John Pettigrew, CEO of National Grid, said power was always available from two adjacent substations unaffected by the fire, but Heathrow's engineers had to reconfigure the power supply and test critical safety systems, leading to the delay.

The airport's regulatory framework allows it to recover money spent by shifting the charges to airlines, who then pass it on to passengers via ticket prices.

Mr Woldbye acknowledged that Heathrow faces a delicate balancing act in determining how much to invest in to make it more resilient in the face of future challenges.

He told the outlet: "We need to look at our resilience...but how far up the supply chain do we need to go, and how much would that cost?

"That's a dialogue we have to have with our airlines, because they are deeply involved in our investments...which has an influence on our charges. That's a very big discussion."

A review of the incident by Ruth Kelly, a board member and former UK transport minister, is expected by May, while the Government has initiated its own investigation.