David Watts Morgan CBE DSO JP (18 December 1867 – 23 February 1933) was a Welsh trade unionist, a Labour politician, and a Member of Parliament (MP) from 1918 to 1933, described as "[straddling] the transition in south Wales miners' politics from Lib-Labism to socialism, but ... never fully representative of either".
Born in Skewen in 1867, Morgan began to work in coal mines from the age of eleven. He was elected unopposed to Glamorgan County Council in 1902, in which year he also joined the newly-founded South Wales Miners' Federation. He enlisted in 1914, and encouraged Rhondda miners to enlist in the army in 1914 following the outbreak of the First World War, for which he was appointed Commander of the Order of the British Empire. He initially served in the Welsh Regiment, before becoming a lieutenant-colonel in the Labour Corps. Morgan was awarded the Distinguished Service Order for bravery at the Battle of Cambrai in 1917, earning him the nickname Dai Alphabet in South Wales. In February 1918, he was selected as the Labour candidate for the newly formed Rhondda East constituency, and was returned again in the 1922, 1923 and 1931 general elections.