His principal business posts were Managing Director of S.G. Warburg (1948-1985) and Vice-Chairman of The General Electric Company (1968-1996). His main public appointments (other than service in HM Forces from 1940-1952) were Deputy Chairman and Managing Director of the UK Industrial Reorganisation Corporation and Director-General for Industry and Technology of the European Commission in Brussels. At various times he also served on the boards of Chrysler Corporation, RJR Nabisco, W.R. Grace & Co., British Aircraft Corporation (now BAE Systems) and International Computers Ltd. He served on boards and advisory boards in Europe and the USA (Blackstone Group and Bain & Co. among them) and is chairman of several international philanthropic bodies in the fields of medicine, education and music. From 1984-1990 he was executive chairman of the South Bank Centre, London's principal arts complex. He was also a trustee of the London Symphony Orchestra and of the Royal Academy of Arts.
- Institute of Strategic Dialogue - Member of the Board of Trustees.
- Chrysler Corporation - Board member.
- RJR Nabisco - Board member.
- W.R. Grace & Co. - Board Member.
- British Aircraft Corporation (now BAE Systems) - Board member.
- International Computers Ltd. - Board member.