Planet Energy hit by 'ransom' blackout threat to the National Grid
Attackers gave the supplier 72 hours before "the lights go out across three counties." Ofgem is monitoring supply to 1.3m homes.
Planet Energy, one of the country's largest grid suppliers, has been given 72 hours to meet a ransom demand or face what attackers call "a coordinated shutdown across three counties."
The threat, received late on Tuesday, came hours after the firm engaged High Tech Inc to review its industrial control systems. Ofgem said it was "monitoring supply to 1.3 million homes" but stressed there had been no loss of power.
The company would not confirm the size of the demand. A spokesperson said only that Planet Energy "does not negotiate with criminals."