Decision not to improve resilience sooner described as ‘unacceptable gamble with our national security’

Hundreds of Britain’s smallest power plants could remain at a higher risk to state-sponsored cyber-attacks until the 2030s despite a successful Iran-linked hack last month, it has emerged.

Officials this week briefed energy bosses on the breach, which is understood to have shut an unnamed small gas power plant for four days last month, and put the industry on alert over the growing cyber threat facing energy infrastructure.