Complexities and divisions over British left-wing responses to the Spanish Civil War between 1936 and 1939 have been well-documented and much studied. This thesis takes forward perspectives from that debate to the aftermath of the Spanish war. It explores the impact of 'Spain', and responses to the defeat, by political parties, individuals, and other groups. It sets these within the framework of disjunctions in British politics between 1939 and 1941, and a decline in political and public discourse on Spain during the Second World War. It finds evidence of the dislocation of lives after the Civil War, but also a determined endeavour to apply the 'lessons' to promote the British war effort, illustrated in the case of Tom Wintringham. The Labour leader, Clement Attlee, emerges as demonstrating personal solicitude for Republican exiles, accompanied by a limited commitment to challenge the Franco regime. The thesis is based on archival sources for the British labour movement, leftwing political parties, and supporters of the Spanish Republic. Responses to the Spanish Civil War were complicated by conflict between the Communist Party, and the leadership of the Labour Party and trade union movement. The defeat of the Republic in spring 1939, and the new urgency of the threat from Germany, changed the calculus. This gave importance to the shaping of early political responses to the end of the Spanish war by the Communist and Labour parties in 1939 and 1940. It was followed by a series of calls on the memory of 'Spain' by these parties, and by Common Wealth from 1942. The continuing threads of 'Spain' in British wartime politics included a diversity of adjustments to the defeat of the Republic by individual International Brigaders, nurses, and other supporters. This was accompanied by fresh responses to the Spanish war. Tom Wintringham secured influence in developing a model of guerrilla warfare for the defence of Britain in 1940-41, drawing on Spanish political and military experience. He was unable to achieve a corresponding impact in proposals for defending India in 1942, or for European liberation after 1941. Clement Attlee, translated from opposition leader to War Cabinet minister in 1940, developed his own nuanced personal and political response to the inheritance of 'Spain'. Attlee demonstrated a strong personal and humanitarian commitment to aid Spanish Republican exiles. He subordinated residual loyalty to the Spanish Republic to support Churchill's policy of conciliating Franco, but pressed a more open view in War Cabinet debates. In late 1944, the signal for left-wing Labour dissent on Coalition government policy was Greece, not Spain. Responses to the defeat in Spain after early 1939 reflected both the diverse character of preceding political engagement during the Civil War, and the new political priorities of the Second World War. They can be characterized as representing a normalization of the experience of the Spanish war. The importance of these developments from 1939 to 1945 has previously been overlooked.