Link here –Victims of the Supergrass System.
The term “supergrass” refers to arrested paramilitaries who divulged the identities of their comrades to the RUC, in exchange for immunity from prosecution. Sir John Hermon did not deny reports that inducements were paid but denied figures as high as £50,000 were involved.The use of the term in North of Ireland began with the arrest of Christopher Black in 1981. After securing assurances that he would have protection from prosecution, Black gave statements which led to 38 arrests. On 5 August 1983, 22 members of the IRA were sentenced to a total of more than 4,000 cumulative years in prison, based on Black’s testimonies alone (eighteen of these convictions were overturned on appeal on 17 July 1986).
By the end of 1982, 25 more ‘supergrasses’ had surfaced contributing to the arrests of over six hundred people.The last supergrass trial finished on 18 December 1985, when 25 members of the INLA were jailed on the evidence of Harry Kirkpatrick. Twenty-four of these convictions were later overturned on 23 December 1986.