The victory of Gwynfor Evans in the 1966 Carmarthen by-election is often seen as a watershed moment for Welsh politics. More than 40 years after being founded, Plaid Cymru had its first MP.
But by-elections can produce flukes, and just as important for Plaid were the general election wins in February 1974 at Caernarvon and Merioneth for Dafydd Wigley and Dafydd Elis Thomas.
As Lord Wigley turns 80, it seems an appropriate time to reflect with him on the significance of his political career, the state of Welsh politics and how future events may unfold.
