Sandro Kopp

Tilda Swinton and her real-life partner Sandro Kopp cameo tonight; he plays art teacher Dylan Shwarz while she's his mute assistant Elke. "All human interaction is social sculpture," Shwarz tells his band of schoolkids, who must make artworks based on tales the patients tell them. "Well, they're all doolally, deaf or asleep, so good luck to you," retorts Den - who's in for a surprise later. Last in the sublime series, and therefore the last time Richard Hawley croons that lovely song over the credits - at least for now.