A girl of about five bumbles to the front of the Olivier stage and sings. She fiddles with her yellow jumper, and furrows her face in childish concentration. Whether she knows it or not, Helen Adesanya is stood in a spot where few get to stand: front-and-centre of the biggest stage at the National Theatre – the nation's main stage.
The Olivier's a symbolic space, and Pericles gives it to the public for the very first time. In that, it's a landmark; not the first project of its kind, but a big shift as to what (and who) the South Bank's stages are for. Shakespeare's island-hopping odyssey is played by all and sundry. Teenagers with bubblegum hair, knock-kneed grandmothers, kindergarten kids waving to mum. There are cheer squads, Indian drummers and Bulgarian choirs. Cockney accents, Jamaican twangs. Headscarves. Wheelchairs. People like us.
Taking a model pioneered in New York, the National's first Public Acts performance prises Shakespeare's play open for a vast community cast – 200 people from all walks of life, of all shapes and sizes, ages, accents and ethnicities. It makes a show of diversity – real diversity – and Emily Lim's exuberant staging celebrates the act of coming together across cultures.
In Chris Bush's watered-down verse adaptation, which dwells most of all on the notion of home, Ashley Zhangazha's Pericles sets out over seas and comes across a succession of singular island tribes. On Tarsus, Garry Robson's Cleon rules over anoraked fishermen. Ayesha Dharker's Simonida leads floral-garlanded festivities on Pentapolis, while Kevin Harvey's RuPaul-a-licious party queen revels with sequinned scenesters on the Ibiza-style isle of Mytilene. En route, Pericles picks up, loses and rebuilds a family – proof that love transcends borders and that people, not places, are the heart of any home.
That's true of theatres too, and Pericles floats entirely on spirit – the same one that powered the Olympic Opening Ceremony six years ago. Ramshackle in parts, it feels a lot like a giant, ocean-themed gang show: Shakespeare meets Britain's Got Talent. Cameo turns from dance troupes and ska bands prove the breadth of performance nationwide, while Jim Fortune's sing-a-long songs and Robby Graham's set pieces flood the stage with seas of people. The joy is watching ordinary folk come out of their shells, and Fly Davis' ebullient fancy dress costumes – cardboard sea creatures and colourful wigs – instil a carnival spirit into the whole.
Sombre moments still cut through – Zhangazha's mute-with-grief Pericles mourning his lost wife and daughter with a newfound stately grace – but fun mostly comes first and it stops the show swelling into something transformative or profound. Participation, here, counts for little more than itself, and Lim rarely mines meaning or metaphor out of inclusion. Other projects have, from the am-dram mechanicals of the RSC's Midsummer Night's Dream to the civilians standing in for the soldiers lost a century before in Jeremy Deller's we're here because we're here. Public Acts has opened the doors to the National – good thing too, and not before time – but to grow into great art it must make something more out of that.