Carmarthenshire councillor resigns after 50 years 10 November 2014 Last updated at 15:54 A by-election is to be held in Carmarthenshire following the resignation of a councillor who served the area for more than 50 years. In a letter to chief executive Mark James, Independent councillor David Thomas, known as "Dai Trelech," confirmed he would be standing down "in view of his declining health." The by-election to replace Mr Thomas will be held on 11 December. Nominations papers for the ward must be submitted by Friday, 14 November.