The KGB secretly plotted to attack the UK at the height of the Cold War by polluting Scotland’s coastline with radioactive waste, it was revealed this weekend.

Masterminded by a Soviet spy based in London, the plan involved dumping nuclear waste into Holy Loch on the Clyde, which was a crucial base for US nuclear-armed submarines.

The proposed attack was designed to fracture the UK’s ‘special relationship’ with America, by falsely implicating the US military in a devastating radioactive incident, and to stoke Britain’s anti-nuclear movement.

Details of the shocking plot have been unearthed from declassified FBI files by security expert Richard Kerbaj and are revealed in an explosive book about the extraordinary life of Oleg Lyalin, a Soviet agent who defected from the KGB in 1971.

Lyalin claimed to be a ‘knitwear’ specialist with Russia’s trade delegation in London. But in reality he was a spy attached to Department V, a top secret KGB unit tasked with assassinations, kidnappings and sabotage.