Tom is a Professor of Law and Head of Department at the School of Law, University of Glasgow. He is Convener of the Committee of Heads of Scottish Law Schools and a member of the Joint Standing Committee on Legal Education. He was a Kennedy Scholar from 1980 to 81 at Harvard Law School, completing an apprenticeship at Hughes Dowdall Solicitors and qualified as a solicitor in 1984.

Tom was for several years Convener of the Board of the Legal Services Agency, a community-controlled law centre, and has acted as expert adviser to the House of Commons Select Committee on Scottish Affairs (1996-1997). He has written and edited numerous books. His most recent is Public Law in Scotland (Avizandum, 2006) (with Aileen McHarg).