Trevor has always been interested in politics, both as an activity and a subject of study. He began both simultaneously as at student at the London School of Economics in 1955, where he joined the Liberal Party (when Clement Davies was its leader) and specialised in political science. He became Chairman of the LSE Liberal Society and later Chairman of the Union of Liberal Students, and was a founding member of the New Orbits Group which sought to modernise party policy. He contested the 1959 General Election in West Lewisham, being the youngest candidate of any party that year.
After that, while remaining active in the party serving on various policy sub-committees, Trevor concentrated on an academic career, teaching politics at the Universities of Exeter, Hull, York and California State (USA). He moved to Queen Mary College (later Queen Mary and Westfield College) in 1967 where he was successively lecturer, foundation professor and head of department, faculty dean and deputy principal until 1991 when he was appointed vice-chancellor of the University of Ulster from which he retired in 1999. He also served as chair and president of the Political Studies Association.
Outside of university life, Trevor pursued a number of interests. He was a board member of the Joseph Rowntree Reform Trust Ltd since 1975 and its chair from 1987-1999; he retired in 2007. He was President of the Belfast Civic Trust (1995-99). He developed a strong interest in health policy, having served as vice-chair of the Tower Hamlets Health Authority (1988-91), as a vice-president of the Patients' Association (1988-95) and from 2000 - 02 he was a member of the North Yorkshire Health Authority. He has also been on the boards of the New Statesman, New Society and Gerald Duckworth (publishers).
Knighted for services to higher education in 1996, he became a Liberal Democrat working peer in 1997 and since 2000 have been spokesperson on Northern Ireland in the Lords and on the British-Irish Parliamentary Assembly. In 1999-2000 he served on the Lords Science and Technology sub-committee investigating complementary and alternative medicine and in 2000 was appointed to subcommittee F of the EU Committee which deals with law and institutions. He chaired the Select Committee on Animals in Scientific Procedures (2001-02), was on the Select Committee on the Constitution (2005-08) and currenty sit of the Ad Hoc Select Committee on the Barnett Formula.
Trevor served as Co-Chair of the Liberal Democrat Parliamentary Policy Committee on Northern Ireland until May 2011.
He is an honorary professor of the University of Ulster and was a visiting professor at York and Portsmouth universities.
Married, with two sons and a daughter, he also has four grandchildren.