Quality attracts quality. Reece Shearsmith and Steve Pemberton have developed such a track record over the years that many of the finest actors in the country jump at the chance to appear in their dark imaginings. And the pair are never predictable. You might think you know where they're heading, but then suddenly they veer off in an entirely different direction. The episode tonight, set in a West End theatre, appears to be a re-working of Macbeth, with Macbeth's understudy (Shearsmith) being egged on by Lady Macbeth's understudy (Lyndsey Marshal) to seize the crown. "This is your chance" she says. "All you have to do is take it". It's not quite that simple.

Peter Capaldi is best known as splenetic spin doctor Malcolm Tucker in peerless political satire The Thick Of It. But he's a man of many talents, as he shows to full effect in this subtle spoof documentary, which sees him triple up as writer, director and presenter. It's film buff heaven; the tale of a now-defunct British movie studio, making room for classy cameos from Lyndsey Marshal and Terry Gilliam - and Capaldi's sharp wit.