Kenneth Bulmer has written a lot of sf over the past few decades; one has the feeling that, if he and E.C. Tubb had been abducted by aliens (probably in need of assistance in rescuing their rightful princess from some blueskinned warlord), then home-grown British sf would have been a bit thin on the ground for much of that time.
Wikipedia calls him "an extraordinarily prolific writer", and not just in sf: his pen-names included Alan Burt Akers, Frank Brandon, Rupert Clinton, Ernest Corley, Peter Green, Adam Hardy, Philip Kent, Bruno Krauss, Karl Maras, Manning Norvil, Chesman Scot, Nelson Sherwood, Richard Silver, H. Philip Stratford, and Tully Zetford, and his work also appeared under "house names" for various series.
Apparently the Dray Prescot series of novels, as by "Alan Burt Akers", runs to 52 books in all (a 53rd was "fragmentary and unpublished", as Kenneth Bulmer suffered a stroke then), though Bulmer's greater popularity in Germany means that thus far the last sixteen have only appeared there...or perhaps his popularity in Japan means there are editions available over there too? A shame, I remember the earlier ones as being good fun!
The Fantastic Fiction page shows that his first novel, co-written with A.V. Clarke (when he was "H. Ken Bulmer"), appeared in 1952, and over the next 45 years, well, he kept busy. He was an active member of UK sf fandom, and he broke into the US market successfully, with stories featured in the leading magazines and novels from a number of publishers, including Ace and DAW.
Kenneth Bulmer died in 2005; his Guardian obituary is here, and the SFWA notice is here.
He wrote some fine stories, and deserves to be remembered for them.