 He was elected to a fellowship at Christ's College, Cambridge in 1965, the same year he was appointed to an assistant lectureship at the University of Cambridge.Promoted to a full lectureship in 1967, he moved to the University of Essex in 1971 to be Professor of Economics, before moving again in 1977, this time to the University of Oxford where he was appointed Nuffield Reader in International Economics and elected to a fellowship at Nuffield College.In 1992, he was appointed Nuffield Professor of International Economics, retiring in 2007.