Bookies took £100,000 in bets in the week leading up to last night's final of Britain's Got Talent, while betting on rival show I'd Do Anything slumped to just £13,000.
William Hill took £88,000 in bets yesterday for ITV's show. "It's the biggest day of reality television betting we have ever had," a spokesman said.
The bookies' favourite to win Britain's Got Talent was 12-year-old opera singer Faryl Smith, from Northampton, with odds of 4/6 following her performance in the semi-final.
"You do not have to be a genius to see how good Faryl is. We are confident we have seen the winner," said Rupert Adams, spokes-man for William Hill.
But on the night the viewers' favourite was George Sampson. The 14-year-old breakdancer from Warrington burst into tears on hearing he had won, and said: "I'm speechless. Wow. Just thanks so much, everybody."
Even before he landed the £100,000 prize and a slot on the Royal Variety Performance in December, he was virtually assured of a glittering showbiz future after receiving more than 100 job offers as a result of his appearances, in which he danced under a shower of water to a souped-up version of "Singing in the Rain".
Speaking after the show, he said: "Whenever I dance I try my best, but tonight was something else. It was the greatest performance I've ever done."
In the final, George was up against acts that included an electric string quartet and a street dance team who had made it through to the final, with nearly 11 million viewers tuning in each night last week to watch the contestants whittled down to the final few.
Escala, from London, were among the bookies' front-runners but, like Faryl, failed to make it into the top three. They had won the public vote in the semi-final with a dramatic rendition of the James Bond theme song "Live and Let Die", while the five-piece hip-hop dance crew Nemesis, from Milton Keynes, won the judges over with their nifty footwork.
Other competitors in this year's event included the extreme martial arts duo Strike and a performing dog called Gin.
Saturday night's Britain's Got Talent on ITV went head to head with rival talent show I'd Do Anything on BBC1.
Jodie Prenger, 28, of Blackpool, won the BBC competition and the role of Nancy in a forthcoming West End production of Oliver! produced by Cameron Mackintosh. "All you guys, thank you from the bottom of my heart," she said.
The BBC panel comprised Andrew Lloyd Webber, assisted by John Barrowman from Torchwood, Denise Van Outen and Barry Humphries. But the winner was chosen by public votes alone.