Stakeknife is the code name of a spy who infiltrated the Provisional IRA, at a high level, as a double agent working for the top secret British Force Research Unit. Reports claim that Stakeknife has been working for the British for 25 years.

Stakeknife had his own dedicated handlers and agents and he was important enough that MI5 set up an office dedicated solely to him. Rumors say that Stakeknife was being paid at least 80,000 pounds a year.

Serious allegations have emerged to the effect that innocent lives were sacrificed to protect Stakeknife's identity.

On May 11, 2003, several newspapers named Freddie Scappaticci as Stakeknife. Scappaticci denies the claims.