A fire at Heathrow airport caused by a fault in an unmaintained electrical substation has led to major disruption to air traffic.

The closure of Heathrow Airport in March was caused by a fire caused by a faulty electrical substation component, according to a report by the UK's National Energy System Operator. Ofgem's investigation into National Grid Electricity Transmission has been launched, following findings pointing to a catastrophic failure due to damp. It severely affected air traffic, costing airlines millions of pounds and raising questions about the resilience of UK infrastructure.