The object of this review is to examine recent developments in our understanding of Oswald Mosley's Blackshirts, of Eoin O'Duffy's Blueshirts, and of British and Irish participation in the Spanish Civil War. It argues that fascism can be understood as having three possible phases of development and considers British and Irish fascism from that standpoint. Debates about the nature of British fascism are considered, its attitude towards violence, towards anti-Semitism, towards women, and towards the coming of the Second World War. The review considers the reasons for the movement's failure. It goes on to examine the debate as to whether or not there actually was an Irish fascism in the 1930s. Finally, it discusses recent work on British and Irish participation in the International Brigades and on the performance of O'Duffy's volunteers in Spain.