'Oh Lord', says the preacher in a suitably grave voice, 'do we have the strength to carry out this task in one night, or are we just jerking off?' Maybe Mel Brooks should have asked himself that question about this movie. The screenplay is credited to five writers, and it shows in the confused melange of styles. There are some lovely touches, and a score of lines like the preacher's which start pompous and end crude; or the contrast between picture - archetypal white-haired old lady - and words - 'Up yours, Nigger!' But if part is delightful, a larger part proves that there is more corn in Hollywood than Oklahoma, and a lot is just Hollywood jerking off.