The sixtieth anniversary of the 1956 crisis in international communism provoked a fresh wave of comment on its British dimensions and coincided with the declassification of MI5 files on party historians Edward Thompson and Rodney Hilton. This article approaches the question of communist commitment through a reinterpretation of the Reasoner controversy in which Thompson and Hilton were to different degrees involved. First, it uses the MI5 material alongside existing sources to illuminate tactical and political aspects of the engagement between the Reasoner editors and the party leadership, placing emphasis on the Reasoner’s role as bridgehead of an attempt to reform the party from within rather than as simply a precursor to the New Left.. Next, interrogating Thompson’s claim to ‘communist principle’, it compares his developing interpretation of what this meant and required with the views of a selection of other intellectuals. Far from representing a straightforward assertion of moral conscience against monolithic party bureaucracy, the Reasoner controversy reveals an extremely complex picture of the tensions and constraints involved in communist commitment
