The author joined the International Brigades in Spain as a volunteer to fight against the fascist rebellion led by Franco. He saw action at Cerro de los Ángeles alongside Esmond Romilly and resigned shortly afterwards, staying on in Madrid as a war correspondent. Within a few weeks, most of the British volunteers in his battalion were dead and he had been chased out of Spain as a deserter. Single to Spain is his memoir of those experiences, first published in 1937.
He soon returned to Spain and was one of the first journalists on the spot to report on the bombing of Guernica in April 1937. Escape from Disaster is his report on the fall of Barcelona and his desperate dash for the border in January 1939, first published in 1940.