Warren, with his brother Gary Pleece, wrote and drew three issues of a self-published comics magazine called Velocity between 1987 and 1989. A satirical collection of stories, there were no recurring characters, but many recognisable caricatures from politics and pop culture. The fourth issue was published by Acme Press in 1990. Their first non-self-published work appeared in Escape magazine.
Warren Pleece also collaborated with Woodrow Phoenix on Sinister Romance, a comic published by Harrier Comics. He then collaborated with Irish writer Garth Ennis on the strip True Faith, serialised in Crisis and eventually published as a trade paperback. True Faith sparked some controversy in the UK with an article in the Daily Mail due to its story being critical about Christianity.
Pleece contributed Second City Blues to the comic 2000 AD, which was a series set in a futuristic Birmingham, with teams playing a deadly sport similar to the one portrayed in the film Rollerball.