A Norwegian pensioner convicted of spying in Moscow says he was wrong to trust an intelligence officer who recruited him to pass on payment for secrets about Russia’s atomic submarine fleet.

Frode Berg has just returned home after complex negotiations led him being included in a spy swap between Russia and Lithuania.

His arrest and conviction for espionage has caused controversy in Norway, where many criticise the Nato country’s use of a civilian in risky intelligence operations - especially when tensions between the West and Russia are so high.

Sarah Rainsford has been to meet Frode Berg in Norway where he is preparing to return to his hometown.