Percival returned to the United Kingdom in September 1945 to write his despatch at the War Office but this was revised by the UK Government and only published in 1948. He retired from the army in 1946 with the honorary rank of lieutenant-general but the pension of his substantive rank of major-general. Thereafter, he held appointments connected with the county of Hertfordshire, where he lived at Bullards in Widford: he was Honorary Colonel of 479th (Hertfordshire Yeomanry) Heavy Anti-Aircraft Regiment, Royal Artillery, (T.A.) from 1949 to 1954 and acted as one of the Deputy Lieutenants of Hertfordshire in 1951. He continued his relationship with the Cheshire Regiment being appointed Colonel of the Cheshire Regiment between 1950 and 1955; an association continued by his son, Brigadier James Percival who became Colonel of the Regiment between 1992 and 1999.