Sailors in the Black Sea faced a missile system they could not see, while the UK spent decades mapping the riverine arteries of Eastern Europe to find where the Soviet Bloc's naval power met the land.
Kept secret in the UK National Archives, a technical assessment of Soviet jamming gear shows how the Kremlin blinded Western sensors to protect its most lethal naval assets
Filed alongside Soviet river lines and electronic nicknames, the technical assessment of one man remained locked in the Ministry of Defence archives for decades.