Internal Security Unit

The Internal Security Unit (ISU) was the counter-intelligence and interrogation unit of the Provisional Irish Republican Army (IRA). This unit was often referred to as the Nutting Squad.

The unit is thought to have had jurisdiction over both Northern and Southern Commands of the IRA, (encompassing the whole of Ireland), and to have been directly attached to IRA General Headquarters (GHQ).

The group was believed to have had a number of briefs:

The ISU was believed to have unlimited access to the members, apparatus and resources of the IRA in carrying out its duties. Its remit could not be countermanded except by order of the Army Council.

Depositions obtained as part of its operation would ideally be noted on paper, and if possible recorded for the purposes of propaganda.

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