An inquiry has found that an electrical substation fire that shut down Heathrow Airport in March was caused by a preventable technical fault identified almost seven years earlier.

A fire at an electrical substation that forced a shutdown at London's Heathrow Airport in March was likely caused by moisture entering electrical components, a problem first flagged in 2018, a report said Wednesday.

A report found that moisture affected parts at a nearby electrical plant that supplies Heathrow with power, causing a fire.