Principal photography took place between 7 October and 22 December 2010. Studio scenes were shot at a former army barracks in Mill Hill, North London. Blythe House in Kensington Olympia, West London, was used as the exterior for The Circus. The interior hall of Budapest's Párizsi Udvar (Paris Court) served as the location for the café scene in which Jim Prideaux is shot. Empress Coach Works in Haggerston was used as the location for the Merlin safe house. Other scenes were filmed on Hampstead Heath and in Hampstead Ponds, where Smiley is shown swimming, and in the physics department of Imperial College London.