Originally dated as 1944.
Peter Dunton writes, on Facebook: Likely to be later than 1944. The Cyclemaster was not produced til 1950?, actually had one of these bicycles bought with Christmas tips from my paper round,and on reaching the age of 16 a cyclemaster engine was attached,In 1956 the bicycle cost me 3 pounds 10 shillings.

The Emu page on Cyclemaster says: "...were motorcycles produced from 1950 to 1960 by EMI at Hayes in Middlesex."
Image courtesy BuyVintage.com