This thesis examines the Scottish Presbyterian Churches anti-Irish campaign in the inter-war period with particular emphasis on the governmental response. It can, and has been, argued that the Church campaign was driven more by sectarian sentiment than by any other motive, however, the Church made a determined attempt to make their case on racial grounds. Discredited as those theories now are this thesis will carefully examine intellectual basis of the Church’s case. It has not thus far been considered how much the Church’s arguments were influenced by academic opinion in the United States and by the American experience of immigration restriction. It has also been argued that politically the campaign was a failure as no measures to restrict Irish immigration were ever imposed. Equally, it has been held that politicians of all parties were either hostile or indifferent to the Church campaign. It will be demonstrated here that this was far from the case and that the Church had its supporters on all sides of the political divide and that at various times the issue was seriously considered by Governments whether Unionist, Labour or National and that arguments for restriction did not emanate solely from the Scottish Churches or indeed solely from Scotland.