Before the war John Jones and Dei Robert Jones were quarrymen in Blaenau Ffestiniog, where they were used to working underground. During the First World War both joined the Royal Engineers, serving as sappers on the Western Front. John Jones was wounded by a bomb on 1 July 1916. He was discharged in July 1917 being no longer fit for active service: he had spent one and a half years in the army, and seven months in the Army Reserve. He walked with a limp afterwards, and bought a horse and cart to deliver coal to houses in Blaenau Ffestiniog.