MOLE

Although this term, as applied in an espionage context, dates back to Francis Bacon, the modern usage originated with novelist John le Carré, himself a former Secret Intelligence Service officer, and applies to a particular type of penetration agent, a mainly (but not exclusively)  Cold War phenomenon. Theoretically, the mole burrows deep underground and deliberately maneuvers itself into a position where it can inflict maximum damage. This implies a spy already recruited before entering the employment of a target organization, which may not necessarily be an intelligence agency. According to this narrow definition, classic examples include Olga Gray and the Cambridge Five in England, Georges Pacques in France, Gunter Guillaume in Germany, George Trofimoff in the U.S. Army, Ian Milner in Australia, and Arne Treholt in Norway. Another definition, widened to include those who volunteered their services after they had gained access to classified information, would include John Walker, Aldrich Ames, Robert Hanssen, Oleg Penkovsky, Dmitri Polyakov, Gilles Brunet, Ric Throssel, and Stig Wennerstrom. Accordingly, the term may be applied to exceptionally damaging spies who may have acted out of variety of motives.