From the MkI cruciform to the No9, this spans the entire production of bayonets designed for use with the No4 Rifle.
Most commonly referred to as the "Spike Bayonet" (or tent peg), was also made by numerous manufacturers and in several different Marks.
South African variation of the No9 Mk1 Bayonet (Left), Actual No9 Bayonet (Right)
Designed to fit the No4 MkI and the Sten submachine gun. It featured a swivel type pommel to accommodate both weapons. It was quickly retired to the storeroom shelves for all but parade use. That is to say it was not popular, or very functional.