King Arthur epic Excalibur in 1981. Director John Boorman cast him opposite Helen Mirren as Morgana over the protests of both actors; the two had previously appeared together on stage in Macbeth, with disastrous results, and they disliked each other intensely. It was Boorman's hope that the very real animosity that they had towards each other would generate more tension between them on screen. Williamson gained recognition from a much wider fanbase for his performance as Merlin. A review of Excalibur in The Times in 1981 states: "The actors are led by Williamson's witty, perceptive Merlin, missed every time he's off the screen." According to Mirren, she and Williamson, free from the problems with Macbeth, "wound up becoming very good friends" during Excalibur. Some of his other notable cinematic performances include as a troubled Irish soldier in the 1968 Jack Gold film The Bofors Gun; in 1975 as an intelligence officer in apartheid South Africa in The Wilby Conspiracy (starring Sidney Poitier and Michael Caine); as Sherlock Holmes in the 1976 Herbert Ross film The Seven-Per-Cent Solution; and as Little John in the 1976 Richard Lester film Robin and Marian. Additionally, he portrayed an MI6 bureaucrat in The Human Factor (1979) (adapted from a novel by Graham Greene); an alcoholic attorney in I'm Dancing as Fast as I Can (1982); a colonel in the Cincinnati Gestapo in the Neil Simon comedy The Cheap Detective; Lord Louis Mountbatten in Lord Mountbatten - The Last Viceroy (1985); the dual roles of Dr. Worley/The Nome King in Return To Oz (1985); Father Morning in The Exorcist III (1990); Badger in the 1996 movie adaptation of Kenneth Grahame's Wind in the Willows; and as Cogliostro in the 1997 movie adaptation of Todd McFarlane's comic book Spawn. Williamson made a major contribution to the documentary John Osborne and the Gift of Friendship, recalling episodes from his long professional relationship with Osborne. Recorded excerpts of his award-winning stage performance in Inadmissible Evidence also feature in the video. Williamson was known for throwing onset tantrums and onstage antics. During the Philadelphia tryout of Inadmissible Evidence, a play in which he delivered a performance that would win him a Tony Award nomination in 1965, he punched the equally mercurial producer David Merrick. In 1968, he apologised to the audience for his performance one night while playing Hamlet and then walked off the stage, announcing he was retiring. In