This article examines the case of the first Irish journalist to be imprisoned for refusing to reveal his sources. In his capacity as political correspondent with the Irish Press, Joseph Dennigan (1910–1950) was called as a witness in a case in December 1933 against a member of the ‘Blueshirts’, a quasi-fascist organisation. Dennigan declined to identify the official sources who he consulted in writing an article about the prohibition of the organisation. The decision to impose a one-month sentence on the journalist generated considerable political reaction and extensive coverage in the Irish and international press. Drawing on Dennigan papers, this article examines the contempt case and also issues that arise from this particular episode, specifically government transition and politician-source relations.