David Ian Marquand (1934-2024) was educated at Emmanuel School, Magdalen College and St Antony's College, Oxford and at the University of California, Berkeley. He taught at the University of Sussex and occupied the chair in Politics at the University of Salford and University of Sheffield and later became the Principal of Mansfield College. Marquand's academic career consisted of writing for Encounter and The Guardian, as well as writing multiple books including Parliament for Europe (1979), The Unprincipled Society (1988), The New Reckoning (1997) and a biography of Ramsay MacDonald (1977) among others. His political career began when he was elected the MP for Ashfield from 1966-1977 which he then left to work as Chief Advisor for the European Commission (1977-1978).

Marquand was affiliated with the Labour Party until he joined the Social Democratic Party (SDP) in 1981 which then merged with the Liberal Party to become the Liberal Democrats. Marquand remained with the Liberal Democrats until he re-joined the Labour Party in 1995. In 2016 he once again left the Labour Party to join Plaid Cymru.

Marquand was married to Judith Marquand, with whom he had one son and one daughter. Marquand wass the son of Hilary Adair Marquand, a former politician and economist.