Alexandra Burke has been crowned winner of the 2008 series of The X Factor, beating competition from boy band JLS.

The 20-year-old – who had been the bookies’ favourite – wins a £1m record contract, while her first single, a cover of the Leonard Cohen song Hallelujah, is tipped to be this year’s Christmas number one.

Both JLS and Alexandra performed their versions of the single after they were voted through to the final two, and both received warm praise.

“They are the best band we’ve had on the show by a mile,” Dannii Minogue said afterwards, while Simon told the four-piece, “you deserve your place in the final.”

However it was Alexandra who won the public’s hearts with her version – and wowed the judges.

“You are going to be a big recording artist,” Louis Walsh told her, while Simon Cowell was literally blown away. “I’m sorry, that was just unbelievable,” he said, “That was seriously incredible. You gotta win.”

Alexandra, who was the last of Cheryl Cole’s acts in the show, was overcome with emotion after learning she had won and was virtually unable to speak – but she recovered enough to thank her fans.

“This is for everyone who voted for me,” she said I love you, I swear to God. Thank you for making my dreams come true, and I am the happiest girl alive, and Cheryl I love you so much.”

Simon Cowell – whose own act Eoghan Quigg finished third earlier in the evening – was also delighted at the result.

“I’m rarely speechless but I am now,” he said. “Alex, you deserve it. I know this show isn’t everyone’s cup of tea but for everyone who has watched it, voted, written about it, thank you very much indeed.”

Alex’s win is also a victory for Cheryl, who was completing her first season as a judge and mentor on the show.

It is the second year running that a newcomer on the judging panel has won, following Dannii Minogue’s victory with Leon Jackson in 2007, the year she made her debut on the show.

However this year Dannii was the only judge without an act in the final.

Earlier in the evening Alexandra had won praise from the judges with a trio of songs – including the Christmas carol Silent Night and You Are So Beautiful, which she performed earlier in the series. She also duetted with Beyonce on the song Listen.

“You took my breath away,” Dannii Minogue told her, while Cheryl couldn’t hide her admiration for her act.

“Thank you Alexandra,” she said after her last performance, “you have made this the most special night of my life.”