To commemorate this, John Nathan-Turner chose silver as a theme for the story. Kevin Clarke contacted Andrew Cartmel and asked if he could write a script for the series. The only slot left was the special and Clarke claimed to have the perfect script. In fact, he didn't, but when he met with Nathan-Turner, he proposed to ask the question: who is the Doctor? (DOC:Industrial Action) Arundel Castle doubled for Windsor, and several figures from the history of Doctor Who turned out to play tourists, including Vere Lorimer, Nicholas Courtney, Fiona Cumming, Peter Moffatt and Kevin Clarke himself.