Born the son of a Llangollen policeman,[1] he was educated at Grove Park Grammar School, Wrexham, and at Peterhouse, Cambridge, he graduated with a degree of LLB and an MA in Classics.

Having been appointed an Officer of the Order of the British Empire (OBE) in the 1982 Birthday Honours,[2] Thomas was created a Life Peer as Baron Thomas of Gresford, of Gresford in the County Borough of Wrexham on 30 September 1996,[3] whereupon he took the Liberal Democrat Whip.

His political interests include Hong Kong, China, criminal justice, and Wales.

Lord Thomas was a vice-president of the Lloyd George Society until February 2012, when he was elected president.

Lord Thomas is the honorary president of the Hong Kong Welsh Male Voice Choir[4]