sentences:  In the 1980s, the Belfast Brigade was hard hit by the use of supergrass informers.These were IRA men who were either recruited as informers by the RUC or who were offered immunity from prosecution in return for testifying against other IRA men.Although the supergrass system was ultimately not very successful in securing the conviction of IRA men, it led to many IRA volunteers being arrested and detained for long periods while they were awaiting trial.