It’s probably a good idea to have a coffee or three before seeing David Mercatali’s revival of Blue Heart, Caryl Churchill’s 1997 double-bill of tongue-twisting, head-spinning wordplay. Because this is Churchill as theatrical experimenter – as opposed to Churchill as political commentator, feminist trailblazer, or apocalyptic doom-monger – and both plays, Heart’s Desire and Blue Kettle, require the audience to remain on their toes from start to finish. It is a uniquely hypnotic experience.

In Heart’s Desire, a discordant family await the imminent return of a loved one from Australia, passing the time before the doorbell rings by bickering endlessly. And I mean endlessly. Over the course of half an hour, they enact the same conversation 27 times, each time progressing a few sentences further before the lights go out and they return to the beginning. Sometimes it happens unexpectedly. Sometimes it happens because a horde of schoolchildren invade. Sometimes it happens because two balaclava-wearing gunmen storm in and execute the family. Sometimes it happens because a ten-foot tall bird wanders through the kitchen. It’s that sort of play.

And Mercatali has done a tremendous job of staging it, particularly considering Churchill’s impossibly frank stage directions. Under his direction, the cast – kudos chiefly to Andy de la Tour, Amelda Brown and Amanda Boxer – move with gloriously synchronised fluidity, flawlessly repeating the same actions, the same dialogue, the same facial expressions over and over again. What emerges, once the technical dazzle wears off, is an intricate, absurdly comic piece, in which the ever-insightful Churchill hints at the chaos, violence and love that lurks beneath our everyday life.

In the darkly funny Blue Kettle, a cynical, 40-something conman (Alex Beckett) cheats elderly women out of their cash by pretending to be the long-lost son they gave up for adoption at birth. But as gullible granny after gullible granny is scammed by this perversely likable lowlife, the play is slowly invaded by two seemingly innocuous words – ‘blue’ and ‘kettle’ – until all dialogue becomes unintelligible. And then the words themselves begin to collapse.

Again, Mercatali handles some intimidatingly complex material with style and subtlety. Beckett is superb, managing to balance a cold, chameleon-like sliminess with a compelling aura of loss, while simultaneously juggling the increasingly dense dialogue. Its technical challenges so proficiently overcome, Blue Kettle reveals itself not just as a supremely intelligent theatrical experiment, but as an enigmatic comment on the usefulness – or, perhaps, the uselessness – of language in moments of overwhelming, inexplicable emotion.

It hasn’t been a vintage 12 months for Churchill. Here We Go at the National, and both Pigs And Dogs and Escaped Alone at the Royal Court divided critics and audiences alike. Before Escaped Alone returns for a UK tour in the New Year, it’s refreshing to be reminded why she is hailed as one of our most innovative, influential playwrights. And this mesmerising revival of Blue Heart does just that.

Blue Heart is a co-production with the Tobacco Factory Theatres and is playing at the Orange Tree Theatre until November 19.

Photo: The Other Richard