He was the second son of Richard Thomas Darvall and Annie Johnson, of Reading, Berkshire.
One of his younger brothers was the politician and diplomat Frank Ongley Darvall (1906–1987), another was Alan Francis Darvall (1903–1983) who was headmaster of Wells House School in Malvern, Worcestershire from 1933 to 1968.
[3] After attending and later graduating from the Royal Military College, Sandhurst, Darvall was commissioned into the Green Howards on 16 August 1916 during the First World War[4][5] and in 1917 he was awarded the Military Cross for gallantry in Macedonia.
2 Flying Instructors School at RAF Cranwell from September 1940 and as Director of Air Transport Policy and Operations from 1943.
23 Group in February 1950, Commandant of the Joint Services Staff College in 1951 and Commandant of the NATO Defense College in Paris in November 1953 before retiring in April 1956.