A MAJOR power outage that affected homes and transport links across the country was because of a lightning strike.

Around a million customers had their power supplies turned off to protect the network on 9 August when two large generators both went offline around the same time, the National Grid’s interim technical report has revealed.

They called it “an extremely rare event” and has not happened in over a decade.

Little Barford gas-fired power plant, north of London, went offline just after the lightning strike at 4:52pm, with Hornsea offshore wind farm in the North Sea shutting down at almost the same time.

The total generation lost was 1,378 MW, which is more than the 1,000 MW of backup kept by the National Grid at any one time, resulting in power supplies being switched off.

A National Grid Electricity System Operator (ESO) spokesperson said: “National Grid ESO welcomes Ofgem’s investigation into the power cuts of Friday 9th August, following our submission of our interim technical report.

“However, it is right and proper that the investigation looks at the system-wide performance of the energy networks on 9th August, in both the performance of the electricity system, and subsequent significant disruption to transport networks and critical infrastructure.

“National Grid ESO will continue its work of a more thorough investigation and report back in line with Ofgem’s timetable of 6th September.”

Regulator Ofgem has launched an investigation, and a final report from the Energy Emergencies Executive Committee is due in November.

Just days after the event, thousands of residents in Basingstoke were also without power, in an unrelated incident.

1,400 homes in Chineham, including the Medical Centre and traffic lights on the A33, were without power.

A spokesperson for SSE said at the time: “It is simply a fault on the network which SSEN engineers are working to resolve.”