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.

Energy watchdog Ofgem has launched an investigation after a report found a fire that caused the shutdown of Heathrow Airport was due to a preventable technical fault.

Energy watchdog Ofgem has now launched an investigation, after a report revealed the 'catastrophic failure' that caused the fire in March. | ITV National News