The Mousetrap
He became the producer of "The Mousetrap" in 1994. During his time managing the St. Martin's Theatre, he had got to know "The Mousetrap"'s producer, Peter Saunders. Waley-Cohen said, "When [Saunders] wanted to retire at the age of 80, he picked up the phone to me". Mousetrap Productions, of which Waley-Cohen is the sole director, is licensed to produce the play by Mathew Prichard, Agatha Christie's grandson, to whom she gave the rights to "The Mousetrap" when he was nine.