Filming began in September 2006 with the zoo sequence from the second episode, in which Benjamin's team have set Tom up to force out Hyde by placing his son, Eddie, in the lion's den. Writing the sequence at a late stage in the production, Moffat wanted to compare Hyde's natural instinct to kill to that of a lion. This was shot on location at Heythrop Zoo, a private zoo in Chipping Norton run by Jim Clubb, whose firm Amazing Animals specialises in training animals for cinema and television. The Norman Foster-designed building in Chertsey, Surrey, which then housed the European Headquarters of video game designer and publisher Electronic Arts, was used as The Klein & Utterson Institute. A large country estate near Henley-on-Thames and in Bognor Regis was used for some of the scenes whilst on the run and in flashbacks. A disused Boys' school in Gloucestershire, and the Hammer House in Wardour Street, Soho were used in episode six. Filming concluded on 20 December 2006.