Lion in the Sky
The above is a history of RAF Seletar published in 1968.
On Pg 139 the then CO of 209 Sqn in 1949, Peter de Le Cheminant refers to 20 pounders being dropped by hand. He also mentions this 'technique' in his autobiography. 'The Royal Air Force - a personal experience' - ACM Sir Peter Le Cheminant, Ian Allan 2001.