Leopold Scarlett was born in Boscombe Manor, Bournemouth, Hampshire on 17 March 1889, the son of Mrs. Florence B Scarlett and the late Lieutenant Colonel Leopold James Yorke Campbell Scarlett. He joined the Royal Navy as a Cadet on 15 January 1904, was promoted to Midshipman on 15 May 1905 and promoted to Sub Lieutenant 30 July 1908.  He was appointed to the Torpedo Boat Destroyer HMS COQUETTE on 7 June 1909 before joining the battleship HMS HIBERNIA on 29 January 1910.

Leopold Scarlett was appointed to HMS MERCURY for instruction in submarines on 8 August 1910 and promoted to Lieutenant on 30 October 1910.  He was appointed to HMS CORMORANT at Gibraltar for in August 1911. He was invalided home from Gibraltar on 3 December 1912, and was transferred to the Retired List (medically unfit) on 13 June 1913.

He then moved to Brisbane, Australia and, in August 1914, he volunteered for service with the Royal Australian Navy. The date of his appointment to HMS AE1 was 10 August 1914, which was after the submarine had arrived at Sydney. AE1 was patrolling in the St George’s Channel off New Britain on 14th September 1914 when she vanished with all hands.

Leopold Scarlett’s Next of Kin was listed as his brother – Major Hugh Scarlett (later 7th Lord Abinger). He is commemorated on the Plymouth Naval War Memorial on Panel No. 4.