Leonard Davies was born in Birkenhead, Cheshire, on 4 May 1903, the son of Frederick James and Louisa Rose Davies (née Glass). He joined the Royal Navy as a Boy Artificer on 8 January 1919; completed his five-year Engine Room Artificer Apprenticeship and then served in the battleship HMS WARSPITE from 31 August 1923 to 15 August 1924.

He joined submarines at HMS DOLPHIN on 17 October 1924 and served in HMS M3, HMS K12 and HMS K2. Leonard Davies joined HMS H28 on 24 November 1926 followed by HMS L2 and HMS L22 from 1 July 1929 to 30 January 1931. He was then sent to Australia to join HMAS OTWAY on 28 February 1931. After bringing OTWAY back to the Mediterranean he joined HMS OXLEY on 23 June 1931. Leonard Davies continued his submarine service in HMS L22, HMS SEALION, HMS THAMES, HMS UNDINE, and HMS PARTHIAN.

Leonard Davies was promoted to Warrant Engineer on 1 April 1941, and, on 27 October 1941, he was appointed to HMS P611 as the Engineer and then to HMS THORN as the Engineer. On 7 August 1942 HMS THORN, found the Italian torpedo boat PEGASO escorting a steamer off southern Crete. PEGASO saw an escorting aircraft machine-gunning the sea’s surface and investigated. THORN was detected and attacked with depth charges after which contact was lost. THORN did not return from this patrol and is believed to have been lost with all hands in the PEGASO attack.

Leonard Davies was the husband of Dorothy Ethel Davies (née Dewhurst), and he is commemorated on the Portsmouth Naval Memorial on Panel No. 62, Column No.2.

He was Mentioned in Despatches (London Gazette December 1940).