The Riddle of the Sphinx (Inside No. 9) was characterised by Pemberton as a thriller in the style of Anthony Shaffer's 1970 play "Sleuth", while Shearsmith identified the episode as particularly theatrical, in the style of "Sleuth" and Ira Levin's 1978 play "Deathtrap". BBC executives, according to Shearsmith, saw the episode as a cross between "Sleuth" and Willy Russell's 1980 play "Educating Rita" that read as if it had been authored by psychopaths. The executive producer Jon Plowman suggested that the first half of the episode plays out like a radio play. The word-play and tea-drinking in this part of the episode are, in the writers' opinion, very
Willy Roper is too late. Only a few days after his release in May 1996, Arthur suffers a brain haemorrhage on the allotments, and dies the next day in hospital. Arthur's funeral is held and Mark is incensed to see Willy in attendance. He confronts Willy and ends up assaulting him. In November 1996 Willy is sentenced to three years in prison. Introduced in June 1995, Willy plays a key part in the long-running storyline that eventually leads to the exit of one of "EastEnders"' original characters, Arthur Fowler. The actor Michael Tudor Barnes was cast in the role for a six-month