This chapter explores the intelligence war’s impact on the IRA in its urban heartlands of Belfast and Derry City between 1976 and 1998. In Belfast, there was a decline in IRA attacks during this period, partly as a result of infiltration and surveillance. Nonetheless, I argue that there was also a decline in IRA attacks, primarily because of the need to avoid civilian casualties occurring on a regular basis, in order to sustain Sinn Féin’s vote. By the 1990s, the Belfast Brigade had recommenced a commercial bombing campaign that would cause extensive financial damage and necessitate the continuation of security installations and patrols. In Derry City, the IRA’s campaign was more of a persistent nuisance by 1994. But this decline was not because of the intelligence war. Rather, it was largely that the SDLP had begun rebuilding the city for nationalists. The IRA risked a decline in electoral support if they attacked the city infrastructure again. The evidence provided does not suggest that the Belfast and Derry City IRA Brigades called a prolonged ceasefire in August 1994 primarily because of the intelligence war. Chapter 8 also debates the impact of suspected agents and informers on the Belfast and Derry City IRA, including the Stakeknife and Raymond Gilmour cases.

The intelligence war had had minimal impact on the IRA’s campaign by June 1972. Various factors explain the limited infiltration by intelligence services of the city and rural areas where the IRA was operating at that time. In urban areas, IRA support increased following the active role played by republicans in defending nationalist areas, indiscriminate British Army actions against the nationalist community and the lack of political and socio-economic reform by Stormont and Westminster. Other factors unique to rural areas restricted intelligence, included republicans’ long-term sense of injustice at being forced into a unionist-dominated Northern Ireland state in the 1920s. British forces also conducted various indiscriminate security operations in nationalist areas, such as in County Tyrone. These operations provoked further tension. The failure to coordinate British military and RUC Special Branch intelligence on a consistent basis made containing the IRA harder. In addition, IRA barricades in Derry City and Belfast, and the ability of some rural IRA units to use the border to evade detection, meant that surveillance of the IRA via vehicle- or personality-checking systems was difficult. The intelligence war’s failure to significantly erode the IRA’s capacity for conflict partly explains why the British government talked to the IRA in June 1972.

This chapter investigates the intelligence war’s effectiveness against each regional IRA group between July 1972 and December 1975. Whilst the Belfast IRA suffered some operational difficulties because of British intelligence efforts, the Derry City IRA, rural republican units in Fermanagh, Tyrone and south Armagh, and the cells operating in England had not been damaged to any considerable extent by 1975. It is true that the number of deaths caused by the IRA had declined since 1972. But the republican movement had spread further across Northern Ireland and the borderlands of the Irish Republic. The IRA maintained a persistent campaign for reasons explored in this chapter. Northern Ireland remained politically unstable in 1975, and when the IRA called a prolonged ceasefire, this was not out of desperation. This chapter discusses important events in the intelligence conflict between 1972 and 1975, included the discovery by the IRA of the Four Square Laundry intelligence operation in Belfast in 1972.