This thesis sets out to explain the attitude of the British Labour Party towards the conflict in Northern Ireland both before and after the deployment of British troops on the streets of Northern Ireland in August 1969. The first chapter discusses themes in the Labour Party's political thought on nationalism. These themes and others are developed and explored in the second chapter on 'The British Labour Party, Empire and Northern Ireland'. The Labour Party's experience of ethnic conflict in the process of decolonisation is used to set the context for understanding the reaction of the party to `the troubles'. Chapters three to seven consist of a chronological account of the Labour Party's reaction to the Northern Ireland conflict. An attempt is made to suggest what the consequences of Labour's attitude was on the ground in Northern Ireland. This is done through an examination of the Party's relationship with the unionist Northern Ireland Labour Party and the predominantly nationalist-inclined civil rights movement. The importance of British nationalism is emphasised to explain the development of the Party's policy. It is argued that initially the conflict in Northern Ireland was viewed predominantly as a problem of `alienation' but it came increasingly to be regarded as a `colonial' issue.