Key Points:

British police are investigating an alleged attempt to kill a KGB double agent who spied on Russia for British intelligence during the Cold War.

Sky News reported that Oleg Gordievsky, who defected in 1985, was hospitalised after falling ill in November. He believes he was poisoned by a Russian acquaintance, a former intelligence officer who visited him at his safe house in Surrey.

After falling unconscious for 34 hours, he spent two weeks in a private clinic and was initially left partially paralysed. He still has no feeling in his fingers.

Gordievsky, 69, fears he is the latest victim of revenge attacks on defectors.

Alexander Litvinenko, his friend and another former Russian spy, was murdered in London in 2006.