Their arrival is well timed for children who were televisually stuck into the Olympic gymnastics, and these grown-up actor-acrobats are also more plausibly pubescent than many a Romanian 16-year-old.

Dynamo Theatre from Quebec array five performers in front of a 12-foot, graffiti-scrawled, imitation-brick wall (the Quebecois "mur" of the punning title). Bob and Cathy and Mike and Lucy proceed to enact a series of characteristic early-adolescent scenes of flirtation, jealousy and romance, while pesky Ralphie annoys them and keeps the laughs coming.

What keeps this out of sitcom territory is that the "kids" hardly speak. They interact through often-manic, sometimes-lyrical acrobatic and dance moves, and impressive they are too: some of the show's sweetest moments are performed upside down.

At one point Lucy charges on stage singing Let's Talk About Sex, and it's easy to imagine Mur-Mur being used as a module for some relationships-and-sexuality education programme. ("Why was Kathy angry with Michael? Is it sometimes difficult to share your feelings?") That's fine. Just so long as the kids don't learn that the answer to life's problems is to do a backflip off the top of a wall . . .