Heathrow’s outage raises questions about Britain’s resilience

AS THE FIRE blazed, planes were grounded and hundreds of thousands of passengers waited, a question rang out: deliberate sabotage or humdrum system failure? The substation fire that shut Heathrow for most of March 21st turned out to be the latter—prompting a blame game between the airport and Britain’s electricity-system operator. (Heathrow’s chairman, Lord Deighton, also chairs The Economist Group)The ease with which such havoc was caused raises questions about the country’s resilience in an increasingly dangerous world.

The main culprit for the shutdown seems to be Heathrow’s failure to plan for such a fire. It took over 12 hours to reopen, despite having access to two nearby substations. The lack of a plan may have sprung from complacency: Britain has long been thought to have one of the most reliable power systems in the world. Other critical infrastructure assets, including hospitals, appear to similarly lack plans.

National Grid, which operates Britain’s electricity grid, is also under attack. Modern transformers, which increase or decrease voltage for transmission, contain concrete blast walls designed to protect against fires. One reason the fire spread quickly is that the 1960s substation serving Heathrow did not. Experts warn that much of Britain’s critical infrastructure—which includes energy, water, transport, health and defence sites—is poorly maintained.

The shutdown will cost airlines and insurers hundreds of millions of pounds, and will harm Heathrow’s reputation. Analysts at Jefferies, a bank, reckon it could knock as much as 3% off profits at IAG, the parent company of British Airways, which operates half of all flights at Heathrow. The airport has backup systems only for critical operations, such as runway lights and the air-traffic control tower. More infrastructure operators may need to invest in backup supply, says Simon Gallagher of UK Networks Services, a consultancy.

At least as remarkable was the speculation by security experts that this could have been a hostile attack. Such an escalatory act would have been considered implausible only three years ago. But the war in Ukraine has seen Russia’s appetite for risk grow prodigiously. Western officials accuse it of sponsoring a campaign of sabotage, which extends from attacks on cabling in the Baltic Sea and railway signalling in the Czech Republic to causing fires in warehouses in Britain and Germany.

Attacks have been planned on Britain’s critical infrastructure before. In the mid-1990s the Irish Republican Army schemed to knock out London’s power supply for months by blowing up six electricity substations. It failed only thanks to moles. Western European countries are starting to grasp their vulnerability to such attacks from a more capable opponent. 

Britain’s national risk register, published in January 2025, judges both system failures and hostile attacks on critical infrastructure as serious risks. It sees conventional attacks as less likely than cyber-attacks, with less than 5% probability within five years, but they would cause greater disruption. The list of targets includes not just the grid and airports, but fibre-optic cables, railways, ports and hospitals.

While this shutdown was merely bad planning, it should be a wake-up call. “I’m not sure we’ve given enough thought to the potential for sabotage,” says Lord Harris of the National Preparedness Commission, a think-tank. “The chaos this event caused is an open invitation to hostile actors.” ■

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