Irving was recalled to the R.A.F. in October 1939 at the start of World War II to serve in the Intelligence Department at the Air Ministry. In March 1940 he was posted to H.Q. British Air Forces in France to be responsible for writing official communiqués and persuading accredited war correspondents to abide by the principle of censorship accepted by their editors. After the surrender of France he returned to the Air Ministry convinced that the system of local defence could have brought the German armoured thrust to a halt. A memorandum he wrote to this effect led to his posting as a Staff Officer to H.Q. 12 Corps., then sparsely equipped to repel a German invasion, to help Peter Fleming to recruit and train an underground force of saboteurs to harass the enemy if a bridgehead was established in Kent and Sussex. When South Eastern Command took control of military operations in that area it was allotted an R.A.F. reconnaissance Wing of three Squadrons and an Air Staff to promote Army/Air co-operation. As Senior Intelligence Officer of 35 Wing, Irving studied and furthered the technical and tactical resources of low level photographic and reconnaissance and the prompt distribution of intelligence derived from it. He ended the War as a Squadron Leader.
After the War he was invited by J. Arthur Rank to produce and design the film adaptation of Sheridan Le Fanu's Uncle Silas (1947). Laurence Irving wrote the highly regarded and definitive biographies Henry Irving, the Actor and his World and The Successors, and two volumes of autobiography, Designing for the Movies: the Memoirs of Laurence Irving, and Great Interruption: An Autobiography 1938-45 (1983).
Laurence Irving was the father of John H. B. Irving and Pamela Mary Irving.