THE Soviet Union used civil airliners to conduct secret Cold War spying missions over Britain.
Some aircraft would switch off their transponders, alerting air traffic controllers to their position before veering off their approved flight paths to carry out aerial intelligence-gathering missions over sensitive targets, papers released under the 30-year rule show.
In a memorandum marked “Secret. UK US Eyes Only”, Defence Secretary John Nott told Margaret Thatcher in December 1981 that the RAF was monitoring the hundreds of monthly flights through UK airspace by Warsaw Pact airlines.
“One incident of particular interest took place on 9 November, when an Aeroflot IL62 made an unauthorised and unannounced descent from 35,000ft to 10,000ft, just below cloud level, to fly over RAF Boulmer, a radar station currently being modernised. It subsequently climbed back to 37,000 ft,” he wrote.
That was not the only example of bad behaviour by enemy spies that year. In August, the Second Secretary at the USSR embassy, V N Lazin, became the first Soviet diplomat for a decade to be expelled for “activities incompatible with his status”.
The Foreign Office informed No 10 that Lazin, actually asenior KGB agent in London, was arrested after trying to get technical and scientific information in the UK from a Portuguese national.