This is not just one of the best pieces of theatre I've seen this year, but one of the best pieces I've seen this century: a show that dissolves all those unnatural barriers dividing children's work from adult theatre, an exhilarating and tenderly moving work, with something for every family member.
Played not in the theatre but in the Polka's exhibition foyer area, the 75-minute piece - putting a day in the life of the Best family on show - is as much installation as performance, celebrating the best things about being a family and confronting some of the worst. And there is not a sentimental bone in its body: it is sometimes joyful, and sometimes brutally honest about the desperate loneliness of family life.
Best Behaviour takes place on stairs that go nowhere, with tables and chairs suspended halfway up walls, and in rooms that have Alice in Wonderland rabbit-holes and baths full of water. Mum is a genuine acrobat precariously negotiating the highs and lows, the children squabble and regroup, alliances are made and lost, and Dad wanders around looking baffled and outnumbered.
The centre of the show is constantly moving: it is not always quite where you are looking, but often on the periphery. Absolutely nothing remarkable happens, yet it is the depiction of the ordinariness of everyday domestic life, and the emotional richness that underlies it, that makes this show so brilliant.
Best Behaviour marks a welcome change of culture at the Polka - and a declaration that this little theatre intends to be a big player.
· Until October 25. Box office: 020-8543 4888.
