Michael Foot had good reasons for resenting Dr David Owen, who played a prominent role in the formation of the breakaway Social Democratic Party (SDP) while Foot was Labour's leader. In Loyalists and Loners (1986), a book of political pen-portraits, Foot duly delivered a blistering attack on Owen, focusing on two charges – that Owen was consumed by personal ambition from an early stage of his career, and that he was an ideological turncoat who had wilfully misused the word ‘socialism’. The present article examines Foot's allegations in the light of various historical sources, including the private papers of both protagonists. It is argued that, though Foot's charges seem devastating at first sight – and have never been refuted by Owen or his admirers – they cannot be sustained after an impartial review of the evidence. This reappraisal provides new insights into Owen's remarkable and controversial career at two pivotal stages – his initial rise to ministerial office, and his decision to leave Labour.