The Americans blame the Russians; the Russians blame the west. Gordon Corera delves into the murky world of subversion, starting with the perspective of Moscow.
Complaints that Russia interfered in America's presidential election are only the latest chapter in a much longer story. Both Moscow and the West have engaged in political subversion over the last one hundred years, in an attempt to undermine the other. This dangerous game has largely been played out in the clandestine world of spies but has burst out into the open at regular intervals. BBC Security Correspondent Gordon Corera tells the stories behind a struggle which still dominates - and often poisons - relations between the East and the West.
Producer: Mark Savage.