Joe McElderry was crowned the winner of The X Factor tonight, in what is set to go down as the biggest night of television of the year.

Viewing figures published tomorrow are expected to show that a peak of nearly 20 million viewers tuned in to see McElderry, 18, overcome Olly Murs in the public vote, to become the sixth winner of the ITV talent show. More than 10 million votes were cast in the final during the weekend. The programme had already achieved its highest Saturday night audience when a peak of 14.5 million viewers tuned into the first half of the final, 54 per cent of the television audience.

McElderry, from South Shields, was the runaway favourite to land the title after a string of heartfelt performances, including a duet with George Michael. He said last night: “I never took much notice of all the hype because as soon as you do I think it can put you off. It was flattering, but just because everyone says you’re going to win doesn’t mean you are. But I’m thrilled. It’s amazing.”

The teenager had solid political backing, with both the Foreign and Culture secretaries coming out in support. David Miliband, McElderry’s local MP, wrote to the singer to wish him luck, while Ben Bradshaw was in the studio to cheer him on in person. Even Gordon Brown took time out from a surprise visit to Afghanistan to send a message of support.

McElderry will now sign a £1 million deal with Syco, the division of Sony Music run by Simon Cowell. He is virtually guaranteed the Christmas No 1 with his rendition of The Climb, an uplifting ballad originally recorded by Miley Cyrus, the American teen singer and actress.

After the Christmas single and a tour around Britain with the rest of The X Factor contestants, McElderry will record an album. In the first two series, the winner’s album was released early in the following year. But Mr Cowell said he would follow plans put in place for former winners Leona Lewis and Alexandra Burke and hold back the album until the show returns.

He said: “What I’ve learnt over the past year is that you can’t make a decent album in less than seven or eight months, full stop. So whoever wins we will take much, much longer with the record and then release it at the time the show would normally return, round about September, October.”

Tonight’s show had an all-star cast, with performances from George Michael and Paul McCartney. Alexandra Burke and Leona Lewis also appeared.