He joined the Labour Party at the age of fifteen, and as a young man he worked in a steel foundry in Llanelli, South Wales.
Morris became an anti-nuclear campaigner in 1957, opposing Operation Grapple X, in which Britain tested nuclear weapons including its first hydrogen bombs over the Pacific Ocean atoll of Christmas Island (now Kiritimati).
After boundary changes he served until 1999, latterly representing South Wales West, an area corresponding to Swansea, Neath Port Talbot and Bridgend.
In the late 1990s, due to the introduction of a list system of proportional representation for British seats, the Labour Party introduced a transitional selection process to determine its candidates for the 1999 European elections.
Indeed, he eventually benefited from the democratisation of the Welsh Labour Party that occurred after Rhodri Morgan took over as leader, when he was elected to represent "South West Wales" (the same area as his former European constituency) on the National Executive Committee of the Welsh Labour Party, on which he served until 2006.