During his periods of office as President of the South Wales Miners Federation (SWMF) from 1936, and as General Secretary of the National Union of Mineworkers (NUM) from 1946, he became one of the most prominent and influential communists in British public life.

[1] Arthur Horner was born in Merthyr Tydfil, South Wales, the eldest surviving son of a family of seventeen children only six of whom lived past infancy.

After a short spell in Merthyr railway goods station he was drawn into coalmining employment in 1915 due to his growing interest in the political radicalism of trade union activists in the nearby Rhondda coalfield.

This small but intellectually inclined Protestant sect, had recognised his potential talent as a preacher and financed a period of training for him as a lay evangelist from which he gained considerable confidence in public speaking and debate.

[5] Horner said that he chose Ireland because he believed the "Irish are the only people waging a war of real freedom"[6] On his return to Britain he was arrested by the police and handed over to the army.

[8] In 1932, imprisoned on trumped-up charges of unlawful assembly, Horner took the opportunity availed to him as Cardiff prison librarian to study The Art of War by Carl von Clausewitz,[9] a work which would significantly influence his future approach to formulating Union strategy and class politics in general – often leading to further conflict with the CPGB Executive.

His increased strategic awareness would leave him strongly inclined against indiscriminate outbreaks of industrial action jeopardising the Union's strength and ability to win concessions for its members.

Having stood unsuccessfully as a CPGB Parliamentary candidate in the 1933 Rhondda East by-election, Horner was elected President of the South Wales Miners' Federation in 1936.

His force of character and intellectual abilities were recognised by civil servants and ministers in the wartime coalition government, who used his enthusiasm and tactical finesse to great advantage to maximise coal production.