Freddie Scappaticci

Freddie Scappaticci was a Northern Irish volunteer in the Provisional Irish Republican Army (IRA), and a leading member of its Internal Security Unit. In 2003, it was reported that Scappaticci had been working for British intelligence, their highest-ranking agent in the IRA, and was known by the codename "Stakeknife". Both the IRA and Scappaticci himself have always denied any involvement with British intelligence.