Leslie was born on 20 January 1910 in Hackney, London to Sydney and Sarah née Siegenberg and he had a younger sister Stella. Their father Sydney was a schoolmaster who worked for the London Country Council, and their mother Sarah, a schoolmistress, were married in London in 1904.
His father wrote a foreword in Leslie’s first posthumous novel: ‘Leslie attended Cowper’s School, where he showed a flair for drawing and modelling. When he left school, he went to St Bartholomew’s Hospital and studied to become a doctor. After two years he decided that he did not want to become a doctor, and for the next three years he devoted himself to pharmaceutical chemistry. Wishing to become an optician, he attended the Northampton Institute, where he produced a Christmas play that he had written. After he had qualified, he practised for about six months before joining the A.B.C. cinema staff and became a relief manager, operating from Canterbury to Dover, Margate, Hythe and London; and he worked in this capacity until the outbreak of war. In his spare time Leslie did a considerable amount of designing and painting, in which he showed great ability in the use of colour; whilst his many penknife carvings show a fertile and creative imagination. He was also a fine pianist, and has entertained many a Mess with his playing.’ Leslie’s artwork, details of his books and letters he wrote can be found on the link below.

Leslie married Annie Sheff in July 1936 and they moved to 30 Cedar Road, Cricklewood, where they were living in the late 1930’s. After Leslie’s death, Annie remarried in 1943.

Leslie volunteered for service on 29 November 1940, serving with 44 Squadron and rising to the rank of Flight Sergeant. He was stationed at RAF Waddington. Lancaster W4180 departed from RAF Waddington at 18.05 on 9 November 1942 on a bombing raid to Hamburg. The aircraft crashed at Buchholz, 16km SSW of Hamburg on the south bank of the Elbe killing all the crew who are buried at Hamburg cemetery.

F/E, Victor Herbert Cusden, 617704.
Pilot, Ronald Easom, 1124509.
W/Op, Rufus Isaacs Gruber, 777670. Rufus was also Jewish and has a page on the website.
A/G, Vallantine Jack Lee, 1395097.
Nav, Joseph Obbard, 1377693.
A/G, Oswald Reynolds Shepperson, 778039.

Publications printed after Leslie’s death.
Perchance to Dream and The Elusive Plot: Stories. London, Alliance Press, Nov 1944.
It’s Haywire! Five fast and furious farces. London, Alliance Press, Jan 1945.
The Vampire, and sixteen other stories. London, Alliance Press, Apr 1945.
Design for Murder, and five other stories. London, Alliance Press, Jun 1945.
Twisted Tales. London, Alliance Press, Jan 1946.
The Heel of Achilles. London, Pan Press, Apr 1946.
Rex on the Trail. London, Alliance Press, advertised.