The Only Way Is Downton (Trafalgar Studios)

While Ibsen's Ghosts prowl the boards above, spectral manifestations of another kind are materialising nightly in the basement space at London's Trafalgar Studios. Over there – can that really be young Mr Crawley? But surely he's…?

It's all smoke and mirrors, needless to say. Or, rather, just the serious talents of actor-impressionist Luke Kempner as he tackles a dazzling array of familiar TV faces (and, more importantly, voices) in his riotous one-man show The Only Way is Downton, an evening of fizzing virtuosity that wowed them at last summer's Edinburgh Fringe and has stopped briefly in London's West End during a UK tour to 30-odd venues.

The show is a blissful flight of surreal fancy. Downton Abbey is on its uppers and the toffs, reduced to dining on quail twizzlers, are desperate to raise money. The solution? Between them they will enter every quiz and reality TV show going. Meanwhile, in a parallel sub-plot, the Dowager Countess declares that she is to be re-married – to a mysterious young beau.

It must be exhausting to perform. The lithe young actor has a voice and a physical demeanour for pretty much everyone (although Anna's South Yorkshire vowels are sadly absent from his repertory) and part of the delight comes from moments of instant recognition. Lady Mary, for example, doesn't even have to utter a sound on her first appearance. She just is, and it's hilarious.

As well as poking fun at Julian Fellowes and his rarefied world ("Scotch? But it's nine o'clock in the morning. We should be drinking sherry"), Kempner turns his mischievous eye to other popular television stars. Some of his barbs are sharper than others: Thomas and Miss O'Brien's appearance on Pointless skewers that show in a few seconds whereas Mrs Patmore and Daisy's participation in The Great British Bake-Off is a touch over-egged.

After the interval Kempner turns the lunacy dial up to eleven in ways I probably shouldn't reveal. Trust me, though, it's worth the wait; unless, of course, you're not a telly-addict, in which case some of the skits will go right over your head (as one of them did mine). Yet anyone who's spent a few Sunday evenings at home with the Crawleys will find plenty to enjoy. And just wait for the wedding – it's a hoot.