The gravest concern about Russia’s impact on nuclear risk is that Moscow might intentionally carry out a cyberattack or a physical attack against a nuclear power plant, thereby unleashing a severe accident, a senior fellow in the Carnegie think-tank’s nuclear policy programme told British MPs.

Mark Hibbs, who specialises in nuclear verification and safeguards and international nuclear cooperation, said this potential threat must be taken seriously, because Russia has carried out indiscriminate ground and air attacks upon civil infrastructure aimed at Ukraine’s population, and because cyberwarfare against targets in Ukraine including electric power grid installations and systems have been widely attributed to Russian actors and interests.

In evidence to a parliamentary roundtable on the Ukraine crisis, Mr Hibbs said there is no record documenting specific cyberattacks against Ukrainian nuclear power reactors, but there are accounts attesting to nearly a decade of cyberwarfare against Ukraine’s electric power grid.