The book has certainly been buried by the popularity of the movie.
Somehow all this morphed into a counterpoint film to Get Carter, on the surface a lighter comedic thriller but with the sinister undercurrents of fascism constantly breaking the surface.
As with Hit Man, the film credited Ted Lewis' Jack's Return Home as its source, not Hodges' film, and again it contains scenes that are directly borrowed from the original, such as the opening train ride.