After The King's School, Canterbury, he read English at St Catharine's College, Cambridge, graduating with a Bachelor of Arts degree.
Honour accepted a position as Assistant director of Leeds City Art Gallery and Temple Newsam House but left after one year to join Fleming in Italy.
Under Honour's editorial guidance, the Style and Civilisation series published in quick succession a group of texts that have attained the status of classics, including John Shearman's Mannerism, George Henderson's Gothic, and Linda Nochlin's Realism.
Honour's contribution, the highly regarded Neo-Classicism (1968), single-handedly resuscitated the scholarly reputation of the period, which had been despised or ignored during the modernist ascendancy.
Honour wrote Venetian Hours of Henry James, Whistler and Sargent (1991) and edited the writings of the Neoclassical sculptor Antonio Canova (1994).