Arthur Lewis Horner was born in Merthyr Tydfil. In 1919 he was elected as checkweigher for Maerdy Colliery. He was one of the founder members of the British Communist Party established in 1920 and played a leading role in the establishment of the Miners' Minority Movement (MMM) in South Wales. Arthur Horner was the first communist to be elected as the President of the South Wales Miners' Federation (SWMF) in 1936, a position he held until 1946. He also held the post of General Secretary of the National Union of Mineworkers from 1946 until his retirement in 1959. He died in 1968.
From the guide to the Arthur Horner, c1915-1965, (Swansea University)