A new report reveals that a power outage at Heathrow Airport earlier this year, which affected over 270,000 passengers, was caused by a «catastrophic failure» of equipment in a nearby substation. Experts attribute the fire at the North Hyde Substation, responsible for supplying electricity to Heathrow, to the failure of a high-voltage electrical insulator called a bushing, likely due to moisture ingress.
The report also notes that two opportunities were missed to prevent the failure, one in 2018 when high levels of moisture were detected in oil samples, signaling the need for bushing replacement according to National Grid Electricity Transmission’s guidance.
Despite these warnings, the report by National Energy System Operator (NESO) highlights that crucial actions were not taken, including the postponement of basic maintenance in 2022. This led to the unaddressed issue culminating in the airport’s closure for approximately 16 hours on 21 March following the fire.
The report further emphasizes that the airport’s internal power network design left it vulnerable, with the loss of just one supply point resulting in critical system failures and operational suspensions.
Heathrow Airport reopened around 6pm on the day of the incident after being closed for 16 hours.
Date of the image: Wednesday, April 2, 2025.
Around 1,300 flights were canceled and over 270,000 air passenger journeys were disrupted. Tens of millions of pounds were lost, and thousands of passengers were left stranded, raising concerns about the UK’s infrastructure resilience. The report stated that more than 71,000 customers lost power due to a fire and subsequent power outage. NEOS CEO, Fintan Slye, highlighted the lack of control in National Grid’s asset management systems. Heathrow attributed the catastrophic power outage to outdated regulation, inadequate safety mechanisms, and National Grid’s failure to maintain its infrastructure. A review led by Ruth Kelly identified areas for improvement, including the airport CEO being unreachable during the crisis because his phone was on silent. Energy Secretary Ed Miliband expressed concern over the NESO report’s findings and mentioned Ofgem’s investigation into possible license breaches related to the incident. The Metropolitan Police confirmed no suspicious nature to the incident. This story is evolving, and updates will be provided shortly. Stay informed by refreshing the page or downloading the Sky News app for breaking news alerts.
A power outage that shut Heathrow Airport earlier this year, causing travel chaos for more than 270,000 passengers, was caused by a «catastrophic failure» of equipment in a nearby substation, according to a new report.
Experts say the fire at the North Hyde Substation, which supplies electricity to Heathrow, started following the failure of a high-voltage electrical insulator known as a bushing – «most likely» caused by moisture entering the equipment – before spreading.
Two chances were missed that could have prevented the failure, according to the report, the first in 2018 when a higher than expected level of moisture was found in oil samples.
Such a reading meant «an imminent fault and that the bushing should be replaced», the National Grid Electricity Transmission’s relevant guidance said.
However, the report by National Energy System Operator (NESO) says the appropriate responses to such a serious issue were «not actioned», including in 2022 when basic maintenance was postponed.
«The issue therefore went unaddressed,» the report adds.
The design and configuration of the airport’s internal power network meant the loss of just one of its three supply points would «result in the loss of power to operationally critical systems, leading to a suspension of operations for a significant period», the report added.
Europe’s biggest airport closed for around 16 hours on 21 March following the fire before reopening at about 6pm.
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