- Emeritus Fellow, All Souls College (from 1996 to 2019)
- Vinerian Professor of English Law, University of Oxford and Fellow, All Souls College (from 1979 to 1996)
- Fellow, Magdalen College, Oxford (from 1954-1979), Emeritus Fellow (1979-2019)
- All Souls Reader in English Law, University of Oxford (from 1964 to 1979)
- Lecturer, University College, Oxford (from 1953 to 1954)
- Assistant Lecturer, London School of Economics (from 1951 to 1953)
- Undergraduate and BCL student, Magdalen College, Oxford (from 1946 to 1951)
- Contract law
- International trade law
- (jointly) Benjamin’s Sale of Goods (London: Sweet & Maxwell, 1974; 9th edn., 2014).
- Frustration and Force Majeure (London: Sweet & Maxwell, 1994; 3rd edn. 2014).
- The Law of Contract (1st ed., London: Stevens, 1962 to 11th ed., London: Sweet & Maxwell, 2003).
- Remedies for Breach of Contract: A Comparative Account (Oxford: Clarendon Press, 1988).
- (with F.M.B. Reynolds) Carver on Bills of Lading (London: Sweet & Maxwell, 2001; 3rd edn., 2011).
- Some Landmarks of Twentieth-Century Contract Law (Oxford: Clarendon Press, 2002; Chinese Translation PUP, 2009).
- Trustee, British Museum (from 1983 to 1998)
- Member, Council, National Trust (from 1984 to 1993)