As a staunch conservative and monarchist, he was alarmed by the rise of communism and in November 1936, shortly after the end of the Siege of Alcazar, broke off from reading for the bar and travelled to Spain where he joined the CarlistRequetés militia under the Nationalists and later the Spanish Legion. He was given journalistic cover for entry into Spain by Collin Brooks, then editor of the Sunday Dispatch, "to collect news and transmit articles for the Sunday Dispatch from the Spanish Fronts of War". He later transferred to the Spanish Legion, where in a rare distinction for a non-Spaniard, he commanded a platoon. Kemp was often badgered by his Spanish comrades about whether he was a Freemason because of his Protestant background. On one occasion, his unit captured a Belfast man who had deserted from the Republican side. Kemp attempted to intervene on the man's behalf but was ordered to supervise his execution. Wounded several times, he continued fighting until he suffered a shattered jaw and badly damaged hands in the summer of 1938, the result of a mortar bomb, and was repatriated to England. Just before he left Spain, he had the unusual distinction of an informal private meeting with Francisco Franco.
Having barely recovered from his jaw injury, Kemp had a chance meeting with Sir Douglas Dodds-Parker, the head of MIR, a small department of the War Office and a precursor to the Special Operations Executive. Becoming one of the earliest pupils at the Combined OperationsTraining School, he sailed in the hold of to Gibraltar and took part in a mission to pursue a German U-boat. A British Destroyer fired at the submarine carrying Kemp by mistake and the mission was abandoned. With further parachute and commando training, he went on several cross-channel raids into Occupied France and was then posted to Albania, where he spent 10 months in clandestine operations. A mission in Poland resulted in his capture by the Red Army. Released after three weeks in prison, he spent two further months in Moscow awaiting an exit visa before he was posted to Siam in the summer of 1945, where he ran guns to the French across the border in Laos. Tuberculosis forced his retirement from the British Army once the war had ended.
Later life
After the war, Kemp sold insurance policies and turned to writing. As a correspondent for The Tablet he travelled to Hungary to report on the 1956 Hungarian Revolution and helped some students escape to Austria. He was present in the Belgian Congo during the troubles that led to independence as Zaire, and he also covered revolutions in Central and South America. He was the foreign correspondent for The Spectator. His first book, Mine Were of Trouble, described his experiences in the Spanish Civil War. Later, No Colours or Crest described his wartime experiences in Albania and Poland as a Special Operations Executive agent and Alms for Oblivion described his postwar experiences in Bali and Lombok. Before his death, he produced an autobiography in 1990, The Thorns of Memory.
