Leslie was born in 1922 in Poplar to Lithuanian born Daniel Chanin and Sophie nee Lampart and he had two sisters Gertrude and Edith. In 1931 Daniel became a naturalised British citizen: ‘Chanin, Gdala [known as Daniel Hanin (or Hainin) ]; Russia; Fried Fish Caterer; 221, East India Dock Road, Poplar, London. 5 October, 1931’.

Leslie enlisted into the RAF in May 1940 and trained as a wireless operator/air gunner. On 28 April 1943 at 20.19, Stirling BF346 departed from RAF Ridgewell on an operation to lay mines in the Quince Region. The aircraft crashed into the Baltic and all the crew are commemorated on Runnymede Memorial.

A/G, Gerald Frederick Heathcote-Peirson, 134917
A/B, Kenneth George Horne, 1320949
F/E, Norman Marshall, 817293
Pilot, Robert Seayears May, 40409
Nav, William Greenhalgh Monk, J/17258, RCAF
A/G, Basil Horace Reeve, 1388458