He was President of the Welsh political party Plaid Cymru for thirty-six years and was the first member of Parliament to represent it at Westminster, which he did twice, from 1966 to 1970, and again from 1974 to 1979.

On entering the House of Commons, he famously failed in his attempt to obtain permission to take the oath in the Welsh language.

The area was mostly English-speaking; at school, he began learning the Welsh language but did not become fully fluent until the age of seventeen.

[citation needed] Evans studied at the University of Wales, Aberystwyth, and at St John's College, Oxford, from where he qualified as a lawyer.

[citation needed] A pacifist, he became active in Heddychwyr Cymru, a Welsh organisation closely associated with the Peace Pledge Union, serving as secretary and editor of a series of pamphlets throughout the Second World War.

A committed Christian also, he declared himself a conscientious objector and was required to appear before a tribunal which, recognising the firmness of his beliefs, registered him unconditionally.

He joined locals Dafydd Roberts and Elizabeth May Watkin Jones in their protest against the closure and flooding of their village Capel Celyn.

"[5] On entering the House of Commons, he famously failed in his attempt to obtain permission to take the oath in the Welsh language.

[8] He also opposed the Vietnam War: after being denied entry to the country as part of an inspection group, he instead protested outside a US air base in Thailand.

[10] In 1980 his threat to go on hunger strike, after the Conservative government reneged on its election promise of a Welsh language television channel, was instrumental in bringing about an early U-turn on the part of Margaret Thatcher, and S4C began broadcasting on 1 November 1982.