Fire at North Hyde electricity substation near Heathrow (UK)

Late on 20 March 2025, at around 23:23 GMT, a fire broke out at the North Hyde electricity substation on Nestles Avenue in Hayes, west London, when one of the site's high-voltage supergrid transformers caught fire. London Fire Brigade deployed roughly ten fire engines and about 70 firefighters, established a wide cordon, evacuated about 150 people, and brought the blaze under control by the morning of 21 March. At least 16,300 homes lost power.

The substation supplied power to London Heathrow Airport, which lost a critical supply and closed for much of 21 March, roughly 16 hours in total. Around 1,300 flights were cancelled or affected and approximately 200,000 passengers were disrupted, with some inbound aircraft diverted to other airports. Because the substation is critical national infrastructure, the Metropolitan Police Counter Terrorism Command initially led inquiries, but after assessment the incident was not treated as suspicious, and police closed the investigation on 25 March 2025. The National Energy System Operator's North Hyde Review found the fire was most likely caused by moisture entering a high-voltage bushing, leading to a short circuit, and criticised National Grid over an unaddressed 2018 fault and maintenance shortcomings, prompting an Ofgem inquiry.

This incident was assessed as non-suspicious and accidental, not an act of sabotage or hybrid warfare. Counter-terrorism officers were involved only because the substation is critical national infrastructure; the Metropolitan Police found no evidence of foul play and closed the case within days. The National Energy System Operator's review attributed the fire to an equipment failure (likely moisture in a transformer bushing causing a short circuit) and highlighted National Grid maintenance failings, including a known fault from 2018 that was not repaired. It is included here as a contextual record of infrastructure fragility rather than a confirmed deliberate attack.