This thesis has as its focus the reactions of the British Government and the Government of the Republic of Ireland to the growth of militant Irish Republicanism and the deteriorating political and social situation in Northern Ireland, during the period 1968-1971. A granular analysis of the various agents of each state allows the complexity of the developing conflict to be shown. What emerges is a picture of strategy and policymaking which emanates from a range of different actors from political, diplomatic, military and civil service spheres. To date, studies of the period have tended to treat the respective states as monolithic; the approach here is to disaggregate, to allow the cross currents ' and purposes of policymaking and strategising, which served the differing agendas of individuals and departments within the states to be fully laid bare. The situation on the ground in Northern Ireland is the backdrop for all state activity, and the analpis offered here of power plays and internal dynamics within the Republican movement itself, shows that movement to be an evolving one during the period, and one which was afforded space to develop and expand by the management of the conflict by the respective states. Northern Ireland, a relative backwater in 1968, was pushed to the top of the political agenda in both Dublin and London, and was on the international stage by 1972. Extensive evidence from primary sources from this crucial period is presented here in an analysis of the activity of the Irish and British States, to gain an understanding of the processes in operation as they reacted to the rapidly-evolving events on the ground.

This thesis focuses on Margaret Thatcher's involvement in policy making in Northern Ireland in the period building up to the Anglo-Irish Agreement (AIA) of November 1985. The findings in this research are surprising: that Thatcher's involvement in Northern Ireland, though intermittent, was much greater than has previously been appreciated, and without this involvement there could have been no AIA. Although we already know a lot from the scholarly research on Thatcher and Northern Ireland, the literatures are somewhat disconnected resulting in a distinct gap in the literature of studies looking at Thatcher's role in Northern Ireland matters. The rolling programme of archival releases under the 30-year rule provides an opportunity to reassess, and revise, what we know already about Thatcher and Northern Ireland in light of the new empirical evidence. This thesis unveils new information which transforms our view of Thatcher and provides new answers to existing questions on Northern Ireland. It fills in the gaps from during this period by focusing on the roles of the Prime Minister and Secretaries of State for Northern Ireland in greater depth than ever before. It will make a significant contribution to our knowledge by bringing new insights into Thatcher's relationship with the Irish Taoiseach, and her determination to do something about Northern Ireland, as well as her relationship with the Secretaries of State for Northern Ireland and key advisors such as the Cabinet Secretary Robert Armstrong. The primary research question that this thesis answers is 'To what extent was Margaret Thatcher involved in policy making in Northern Ireland, specifically from 1979 until 1985, and what was the impact of this?' In order to answer this question, two sub-research questions will also be addressed along the way. The first sub-research question relates to Thatcher as Prime Minister and her style of leadership. For the first time we have key respondent interviews with the full archival record to deepen and enrichen our understanding of the role of the key actors. This will help us to understand what sort of a leader Thatcher was - autocratic and ideological or pragmatic. The second sub-research question relates to Thatcher as Prime Minister and ministerial relations. To understand Thatcher we have to look at her Secretaries of State for Northern Ireland. We can learn about her leadership in Northern Ireland through these relationships, allowing an emerging picture of Thatcher to build up over subsequent chapters in this thesis. In order to be able to answer these questions, this thesis combines rigorous archival research, using newly released government archives under the thirty year rule, and an extensive programme of elite interviews with insights drawn from a political science literature on the core executive. This allowed me to construct a robust historical narrative informed by inter-disciplinary insights, bringing the Thatcher and Northern Ireland literature together in a way which has not been done before.

The thesis considers ethno-territorial conflicts in which there are two conflict groups with corresponding ‘reference states’. ‘Reference states’ are internationally recognised states with co-nationals in the aforementioned disputed territory. The literature on ethno-national conflict regulation largely neglects the potential constructive role of ‘reference states’. In particular, Arend Lijphart’s work on consociational democracy focuses on elite accommodation within the conflict zone, but views other agents as ‘external’ to the dispute. Unlike most of the current ethnic conflict literature, the thesis will use a theoretical approach to derive the features of a settlement, not distil traits from purely empirical research. An informal model is employed assuming that that a military option is not open to reference states and that disengagement from the co-nationals is costly. The actions of the reference state are simplified to four options: remaining at the same level of conflict, escalating the dispute, attempting cooperation, or disengaging from the dispute. The features derived for the resulting transnational consociation settlement are: durable reference state/conational links, bipartisanship within reference states, intergovernmentalism between reference states, and consociational democracy internal to the disputed territory. The thesis then focuses on the post-conflict power-sharing settlements in Bosnia- Hercegovina and in Northern Ireland to investigate the features of transnational consociation in these two cases. The settlement after the Belfast Agreement exhibits the traits of transnational consociation, with a strong intergovernmental Dublin- London axis acting as reliable long-term guarantors of the settlement. By contrast, there is little intergovernmentalism between Zagreb and Belgrade regarding the settlement in Bosnia-Hercegovina. The post-conflict institutions are held together by international agencies that do not have as durable a link to the conflict zone as the ‘reference states’. Therefore, a durable transnational consociation with the ‘reference states’ as guarantors is more likely in Northern Ireland than in Bosnia-Hercegovina.