John Jakob Mendelson (1917-1978), an intellectual on the left of the Labour Party, was born of Polish parents and educated in France, and at the University of London where he took the degree of BSc Econ. He gained experience of industrial affairs by working in factories in the North of England. Service in the Army during World War II brought him the rank of Captain. His connection with Sheffield and its University was close: in 1949 he was appointed Lecturer in Economics and Public Administration in the Department of Extramural Studies, a post which he held until entering Parliament at a by-election in 1959, and he served as Vice-President of the Sheffield Trades and Labour Council. In the Commons he became politically a force on the Left, firstly in the Bevan group and later in the Tribune group of MPs, though his independent viewpoint on various issues led to clashes with other members.

During the debate on German rearmament in 1959 Mendelson joined with Richard Crossman in tabling a Commons motion condemning any possible proposal to provide West Germany with atomic weapons, and he was a leading critic of American involvement in Vietnam, travelling to the United States to discuss American policy with members of the US Government. But after the February 1974 General Election, when many younger and more extreme MPs joined the Tribune Group, his name was omitted from the list of contenders for places on the National Executive Committee of the Labour Party.

[Notes based on the Times obituary 22 May 1978 and entry in Who's Who]