Strictly come merchandising

There's only one thing that this arena tour of Strictly Come Dancing lacks and that's John Sergeant's incomparable paso doble à la sack of potatoes. Apart from that, everything, everything – down to the very last sequin – that has made the BBC show must-see Saturday night television for the past five years is faithfully reproduced here, live on stage.

There's the jaunty ba-da-da-daaa theme tune, the spangly opening credits, the glitzy set complete with difficult-to-negotiate steps and very excellent band (led, impeccably, by Alan Rogers), all four judges and a blonde compère (ex-X Factor hostess Kate Thornton ably filling Tess Daly's stilettos here, with a calm and, at times, nicely cheeky manner). There's even a scandal-baiting phone vote as the audience texts in for its favourite. On this particular evening, there were shades of Sergeant-gate as Julian Clary's hammy hoofing very nearly snatched the winners' glitterball from the tiny clutches of the eventual and very deserving winner, Rachel Stevens.

And there's dancing, of course, performed by eight celebrities and their professional partners, all dressed in gorgeous couture of net, silk, sequins and ostrich feathers. And that's just the guys. There are a couple who can really move (Stevens and Jill Halfpenny), some from the middle of the pack (Cherie Lunghi and likeable, leggy Jodie Kidd), two housewives' favourites (this year's winner, Tom Chambers, and Blue Peter hottie Gethin Jones) and the requisite rhythmically challenged jokers (Clary and rugby ox Kenny Logan). Each dances a ballroom and a Latin dance, resurrecting their greatest hits – Rachel's rumba! Jill's jive! Tom's quickstep! – from the TV show for an endlessly enthusiastic audience that greets each number with knowing nods and appreciative oohs. The judges then give their characteristically barmy comments and scores out of 10; we vote and the results are announced to the sound of that weird amplified heartbeat.

The BBC has hit on a winning formula, so why change it for the tour? A glance around Wembley Arena reveals an audience of excitable children, trendy twentysomethings, middle-aged women on a night out, men looking studiously bored but secretly delighted, jolly, white-haired pensioners – and, behind me, one very, very restless teenage boy – all eagerly waving their scorecards (courtesy of the £10 programmes), debating the finer points of footwork and joining in the dancing with not a jot of embarrassment. With more than 12 million people tuning in each week, there's an endless supply of these wildly diverse fans to fill the stadiums and BBC Worldwide, the corporation's commercial arm, stands to make about £6m from this five-week tour – even after it has paid each of the stars £50,000.

Forget Brown's bailouts: perhaps Strictly can provide the vital stimulus the global economy needs. The BBC has already sold the format to 38 countries worldwide, making it the most-watched television programme on the planet and the corporation's most lucrative franchise, bringing in an estimated £60m a year for licence payers. And now it's milking the cash cow even more with a dizzying array of spin-offs. Last week, BBC Worldwide announced a range of branded products – from iPod covers to pyjamas and, erm, glitterball earphones (no, me neither) – which will join the Strictly workout DVDs, autobiographies and annuals on the shelves.

At Wembley, there is a lot of marketing going on, with merchandise stalls offering overpriced programmes and cha-cha-cha T-shirts and a warm-up act flogging the autobiographies of judges Len Goodman and Craig Revel Horwood at every opportunity. But there's also a lot of show. With tickets priced between £35 and £55 – the same as a West End show, and significantly less than many stadium gigs – it offers good value for money with about 20 numbers performed over the two and a half hours.

Among those numbers, Halfpenny and Stevens excel with technically excellent tango and jive. Jones produces a touching waltz and Logan entertains with a quite extraordinarily stompy paso doble. Chambers, strangely, fails to stand out. Clary brings the house down with his flat-footed routines and quick-witted sparring with the judges, though his repartee does highlight, in screaming neon pink, the distinct lack of personality from the other contestants.

There are also a couple of wonderful routines from the professionals who really let fly when unencumbered by their celebrity partners, luxuriating in the enormous dance-floor as they whirl around in a blur of feet and silk. Clad in about seven gold sequins and seemingly boneless, Kristina Rihanoff offers a particularly stunning show dance. "She was...," sighs my companion, wistfully, "a little wasted on John Sergeant."

The judges, though stilted (and possibly a little scripted?) to start with, soon warm up to their familiar roles. Arlene ever torturous with her similes and stridently lascivious; Len, diplomatic and occasionally barrow-boy crude ("that had more rise and fall than a bride's nightie"); Craig, prissily precise, drawling like a stoned Marlene Dietrich – "that was a darncing disarrster" – and roundly booed at every opportunity; and Bruno, whose comments – "You dance like a naughty demon!"; "You are master and commander of the waltz!"; "You are like Salome dancing for Herod!" – grow increasingly loopy as the night wears on. All four look as if they're having as much fun as the crowd, and gamely – if a little stiffly – join in with the dancing for the pyrotechnic finale.

This is the key to Strictly's success. It has a warm heart. Despite the millions, the marketing and the merchandise, it has yet to become a slick, soulless juggernaut. All involved seem really quite thrilled to be there. Chambers' puppy-dog enthusiasm leads him to trip up his partner Camilla in the first dance. Kidd wobbles her way through a jive like an arythmic giraffe, all the while with a gigantic grin on her face. And Logan, thighs bulging beneath his diamanté kilt, looks like a man who can barely believe his luck as he wraps his meaty paws around Ola's undulating waist in the paso doble. John who?

Touring to 22 February (08700 11 26 26; www.strictlycomedancinglive.co.uk)