The Roman Catholic Church in mainland Britain included a large number of Irish immigrants and their descendants amongst its members, and the parish church often acted as a repository and medium for sustaining a national identity for the Irish. The church building permitted the replication of Irish Catholic symbols and practices, including those of an idealised domestic interior elevated to institutional status, and embodying a familiar and distinctive visual culture and spatial organisation. The parish church also replicated an Irish identity for many through the enactment of public rituals centred on the church building. The church was a site in tension, however, as the Catholic hierarchy aimed to gain acceptability for its members in British society; church buildings therefore often demonstrate its attempts at countering Irish identity with the assertion of Britishness in their symbolic schemes. This essay moves from a thematic discussion of the role of church architecture in negotiating Irish identity in British Catholicism to case studies of buildings illustrating the working out of the Church’s position on this problem. The argument that the Second Vatican Council’s reforms in worship practices and architecture led to a loss of a distinctively Catholic and Irish visual culture is also considered.