The first morning of half term and this West London venue, better known for rock bands and bankable stand-ups, is invaded by thousands of under-sevens and their attendant adults. They have all watched the Icelandic children’s show Lazy Town on television, and the parents seem perfectly happy to part with handfuls of notes to help their charges get as close as possible to their favourite characters: Stephanie with the strawberry hair, super-hero Sportacus and sneery villain Robbie Rotten. Judging by the number of synthetic pink and orange wigs in the audience, plenty of five-year-old girls already think they are the heroine.

For the rest, marketing is in over-drive; there are Lazy Town albums, magazines, dress-up kits, action dolls, backpacks, t-shirts at £10, a mini-garment and - would you believe - yogurt. Even the programme purports to be an “activity brochure” and is simply a rip-off at £6.

So, here we have commercialism at its most rampant. But wait: this loud, garish play-with-music has a message. The television programmes (sold to 100 countries) were conceived by Magnus Scheving, a gymnast who also plays Sportacus on screen. He advocates eating fruit and vegetables (“sport candy”) and taking up outdoor exercise, such as soccer, instead of slumping in front of computer games (and, I suppose, Icelandic television shows).

A shame then, that this admirable advice is muddied on stage by Sportacus keeling over as if poisoned when he has taken a mouthful of sugar before a race; sugar may be bad for you in the long run, but it does provide energy. Sportacus is played here by Julian Essex-Spurrier who is impressively muscled and, along with the rest of the cast, has a suitably over-the-top, cartoonish style.

There isn’t much of a plot. Lazy Town has a rule that only one super-hero can reside therein and dastardly Robbie Rotten (Scott Joseph - surprisingly slim for a black-hearted couch potato) manages to pass off a robot as the superior contender until energetic Sportacus flies in to resume his rightful position with the help of Stephanie (Kimberley Pena) and the Lazy Town kids. Although the connection between sport and Sportacus is well understood, nobody spots the clue in the name Roboticus, a character played by Darren Partridge using break-dancing moves to advantage.

To think that we first met Icelandic gymnasts when the Vesturport company brought their innovative, circus-style Romeo and Juliet to London. This show, for all its colour and noise, has nothing like the same involving relationship with its audience. The children dutifully stamp and fling their arms up when required in Richard Lewis’s production, but they might as well be watching TV really. Theatre is exciting because skilful people can take your imagination on a journey with them, in the same moment and in the company of hundreds of others.

This isn’t so much theatre as a slick and soul-less product.

- Heather Neill