Double Double Act
Double Double Act
© Camilla Greenwell

A massive fart echoes around the Unicorn Theatre: a long squelchy trumpet with a teeny parp to finish. The kids watching Double Double Act go absolutely bananas. They bounce in their seats and laugh their little heads off. It's just too much for them. A fart. In public. From an adult bottom. Hysteria.

It's so rare, in theatre, to see something intended exclusively for children. Kids don't buy theatre tickets. They rarely, if ever, go to the theatre alone. Most children's theatre ends up playing to a mixed audience, adults and kids all jumbled together and artists tend to take that into account. While panto thrives on that dual dynamic, sending double entendres sailing over the littleuns' heads, most shows pander to it more subtly. They might be aimed at kids, they might address kids, but they keep their adult audiences in mind at all times. They're the customers here, after all.

Commercially speaking, the family show is the Holy Grail. It can double a producer's takings in a single shot. You might take a date to Dreamgirls, but you end up block-booking Matilda: mummy, daddy, brother, sister, BFFs, grandma, grandpa, family pet. Before long, the trip's as squished as a bed full of old Buckets. Little wonder, then, that the long-runners of recent years – War Horse, The Curious Incident of the Dog in the Night-Time, Matilda – are those that adults can just enjoy as much as kids.

Key to those shows is that they operate on two levels. All have young protagonists that speak directly to young audiences' experiences, while letting adults into that perspective on the world. Christopher Boone reminds us how overwhelming the adult world can be; Matilda Wormwood, that sometimes you've got to be a little bit naughty.

Sometimes, we adults need to hear things said simply. That's what Theatre-Rites do so well – they make shows for children that speak, surreptitiously, to their adult audiences. The Welcoming Party, currently playing at the Manchester International Festival, does just that. The ways it addresses the refugee crisis and our impenetrable immigration system introduces kids to new ideas, but its straightforwardness, its innocence, lands as an urgent rebuke to us adults as well. The show transcends all delineations of children's or adult theatre. It's just theatre – and all the better for it.

But don't children deserve a theatre all of their own as well, entirely uncorrupted by adult influence? It's not like we wrinklies aren't well catered for, after all. Shouldn't kids get special treatment of their own?

It happens for the very young: Improbable have made an opera specifically for babies, Bambino and the Unicorn's Baby Show is still going strong. (It helps that the audience replenishes itself year on year.) But the older kids get, the more they have to share shows with adults. The volume's turned down, the edges are smoothed off, the tone becomes gentle and sweet – nothing that might give mum and dad migraines. We're happy, but aren't the kids missing out?

Made In China's Double Double Act really brought that home. The show splits its audience down the middle, playing to adults and kids separately and simultaneously. It sets out to show how different our sensibilities, and specifically our senses of humour can be. Its two comedy duos – one big pair, one small – play to please their respective audiences. We get machine-gun punning one second, part Dr. Seuss, part Samuel Beckett. They get mega fart noises. We get a near-the-knuckle gag about paedophilia. They get a good old-fashioned gunging. Is there a crossover?

It's a show that delights its kids by playing primarily and purely to them. At the same time, it lets us see them anew. The kids' reactions, their hysteria and hilarity, is absolutely part of the show. We're watching them laugh, often uncontrollably, at things that leave us plain stony-faced. And vice versa: things we find chucklesome leave them confused. Why is ‘bum' funny? What makes slime so appealing? Why haven't they grasped the innate agony of existence?

What you realise is that children are, essentially, anti-adult. They want us humiliated, by fall or by fart. They push poisonous potions on us and cover us in cat poo. Nothing thrills them more than seeing adults in mortal peril – a knife-throwing finale, adults bound and blindfolded, sends them through the roof. Even the colours they relish are offensive to us: the garish, day-glo green of kids' TV being the height of bad taste. It's an alarming realisation. Your kids probably want to kill you. They certainly want to overthrow their adult rulers. And they really don't want us at their theatre. The whole thing is a big fat fart in our wrinkled old faces.

Double Double Act is at the Unicorn Theatre from 20 June to 10 July.