Has Britain really got talent? Packed houses or a swift return to obscurity beckon tonight as millions of viewers cast their votes in the climax of rival star-making shows.

After weeks of weeding out dancing ferrets and off-key singers, ITV1 viewers will choose the winner of Britain’s Got Talent, Simon Cowell’s latest lucrative series. In the final episode of I’d Do Anything on BBC One, Lord Lloyd-Webber will finally reveal the public’s choice to play Nancy and star in a new West End production of Oliver!

Aware that the denouement of such shows has become a national event, schedulers have reached a non-aggression pact: the programmes will clash for just ten minutes.

The power of the internet means the finalists have already become international stars before a final vote has been cast. Clips of George Sampson, 14, whose “street dancing” routine to Singing in the Rain even charmed the stony-faced Cowell, have received three million views on YouTube.

It is the boy’s hard-luck story, as much as his breakdancing talent, that has won the hearts of viewers. Sampson, from Warrington, started busking because his mother couldn’t afford to pay for his dance classes. If he wins the £100,000 prize, he will use it to pay off her mortgage.

Faryl Smith, a 12-year-old classical singer from Kettering, Northamptonshire, qualified for tonight’s final after flooring the judges with her performance of the Sarah McLachlan ballad Angel.

Even Cowell was impressed. He told the schoolgirl: “When you enter a competition like this, you pray to find someone like you. You are literally one in a million. Anyone hearing you for the first time tonight should remember this occasion because you have the most incredible future.”

Inclement weather has driven viewers to the shows, creating a revival in old-fashioned Saturday-night viewing on terrestrial channels.

Last month, total television viewing was up 10 per cent year on year, to three hours and 45 minutes a day on average, according to the marketing body Thinkbox.

Record companies are already moving in on the singing finalists in Britain’s Got Talent, who include a crooning plumber as well as the child star. The winner’s career will be boosted by a slot on the Royal Variety Performance.

But the BBC has faced criticism that its popular musical-theatre talent shows have given undue prominence to shows in which their adviser Lord Lloyd-Webber has an interest.

The Theatre Royal, Drury Lane, production of Oliver! took £3 million in the first ten days of ticket sales, timed to coincide with the series. Lord Lloyd-Webber’s Really Useful Group controls the theatre and has a share in the ticket sales company.

He replies that staging the Cameron Mackintosh production in his theatre has required him to delay plans to open a sequel to his own Phantom of the Opera.

Winning tonight’s final is no guarantee of a long stage career. Connie Fisher, winner of How Do You Solve a Problem Like Maria?, won plaudits for her West End performance in The Sound of Music and enjoyed a hit album.

But after she finished her role, two concert tours of large venues were cancelled amid talk of poor ticket sales. Fisher is to make her television drama debut as a parking warden obsessed with Elvis in an ITV film, Caught in a Trap.

Paul Potts, winner of the first Britain’s Got Talent series, has become an unlikely global star. The Carphone Warehouse salesman has sold two million albums and topped the charts in 15 countries. He was invited to perform on the Oprah Winfrey show after cracking the US charts.

Cowell is certain to be a winner. Britain’s Got Talent is co-produced by his Syco company, which also created The X Factor. Cowell has already turned the Talent format into a US television hit, making a transatlantic star of Piers Morgan. The judge also maintains an interest in the record sales of his winning competitors.

Mackintosh may provoke a viewer backlash after suggesting that the bookies’ favourite among the Nancy finalists, Jodie Prenger, 28, from Blackpool, was too large to play that role. Lord Lloyd-Webber said: “Cameron thinks she is a bit too big and has more or less said so.”

He himself disagreed, adding: “Jodie could be anybody’s idea of Nancy — I can see it absolutely. She has got a lovely voice and a super personality. She has experience too.”

The final of I’d Do Anything will be screened today on BBC One from 6pm until 7pm and again from 8.45pm.

The final of Britain’s Got Talent will be screened on ITV1 from 6.50pm to 8.30pm and again from 9.30pm.

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