He played a part in the Battle of Cable Street where he says he first heard the words "No Pasaran" and learned of the war in Spain. He enlisted in the 15th International Brigade and left for Spain in September 1937. He fought in the Battle of Jarama and the July 1938 crossing of the Ebro, attempting to recapture Gandesa. He was with Lewis Clive when he died. On 24 August, while defending Hill 666 in the Sierra de Pandols near Gandesa under artillery bombardment and an attack by two rebel battalions, Johnny was severely wounded and temporarily blinded.