He is mainly associated with the role of Sherlock Holmes, which he first played in the BBC's 1964 production of "The Speckled Band". Together with co-star Nigel Stock, who played Doctor Watson, Wilmer was brought back for a further twelve episodes of the "Sherlock Holmes" series. In 1973, Wilmer played author Jacques Futrelle's Holmesian detective Professor Van Dusen in "The Rivals of Sherlock Holmes" for ITV. In 1975, he once again appeared as Holmes (albeit in a supporting role) in Gene Wilder's "The Adventure of Sherlock Holmes' Smarter Brother", with Thorley Walters as Dr. Watson. Wilmer also played Sir Denis Nayland Smith in two of Harry Alan Towers' Fu Manchu films, "The Brides of Fu Manchu" (1966) and "The Vengeance of Fu Manchu" (1967).