The Cats by Nick Sharman (1977): Apocalypse Meow

Scott Grønmark was his name and writing pulp horror paperbacks under the pseudonym "Nick Sharman" was his game. Born in Oslo, Norway, in 1952, he was working in the PR department of New English Library (which is why of course he had to use a pseudonym) when he began his published career with The Cats. It was originally published by NEL in 1977 (below), and then by Signet in America in May 1979.