John Boulting Director, Producer, Screenwriter Roy Boulting Director, Producer Peter Sellers The Rev. John Smallwood Actor Cecil Parker Archdeacon Aspinall Actor Isabel Jeans Lady Despard Actor Eric Sykes Harry Smith Actor Bernard Miles Simpson Actor Ian Carmichael The Other Smallwood Actor Irene Handl Rene Smith Actor Brock Peters Matthew Robinson Actor William Hartnell Major Fowler Actor Roy Kinnear Fred Smith Actor Joan Hickson Housewife Actor Frank Harvey Screenwriter Richard Rodney Bennett Original Music Mutz Greenbaum Cinematographer Teddy Darvas Film Editing Albert Witherick Art Director David Ffolkes Costume Design