Duffy was educated at St Joseph’s RC School, Wolverhampton. He served in the Second World War from 1940 to 1946 in the Royal Leicester regiment assigned to the American 1st Army. He fought at Salerno and Monte Carlo.
He rose in the Amalgamated Union of Engineering Workers, becoming a Divisional Officer in 1969; a member of the Executive Council in 1976; and President in 1978. He was also on the General Council of the Trades Union Congress from 1978 until his death.
- "Encyclopedia of British and Irish Political Organizations" By Peter Barberis,P; McHugh,J; Tyldesley,M p200: London, Pinter, 2000 ISBN 1-85567-264-2
- The Times (London, England), Monday, 9 October 1978; pg. 16; Issue 60427
- ‘DUFFY, Terence’, Who Was Who, A & C Black, an imprint of Bloomsbury Publishing plc, 1920–2016; online edn, Oxford University Press, 2014 ; online edn, April 2014 accessed 20 July 2017
|Trade union offices|
| President of the Amalgamated Engineering Union