dˈʊɹɹɪŋ hɪz pˈiəɹɪədz ʌv ˈɑːfɪs æz pɹˈɛzɪdənt ʌvðə sˈaʊθ wˈeɪlz mˈaɪnɚz fˌɛdɚɹˈeɪʃən ˌɛsdˌʌbəljˌuːˌɛmˈɛf fɹʌm nˈaɪntiːnhˈʌndɹɪd θˈɜːɾi sˈɪks, ænd æz dʒˈɛnɚɹəl sˈɛkɹətɹi ʌvðə nˈæʃənəl jˈuːniən ʌv mˈaɪnwɜːkɚz ˌɛnjˌuːˈɛm fɹʌm nˈaɪntiːnhˈʌndɹɪd fˈoːɹɾi sˈɪks, hiː bɪkˌeɪm wˈʌn ʌvðə mˈoʊst pɹˈɑːmɪnənt ænd ˌɪnfluːˈɛnʃəl kˈɑːmjuːnˌɪsts ɪn bɹˈɪɾɪʃ pˈʌblɪk lˈaɪf.
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.