Alexandra has Christmas number one 'in the bag'

'X Factor' winner Alexandra Burke already has the Christmas number 1 “in the bag” according to one of Britain’s biggest music retailers.

The 20-year-old singer, who won a £1m (€1.1m) recording contract after wowing millions of viewers during Saturday night’s final, released her debut single 'Hallelujah' for download yesterday.

HMV today confirmed the single was its fastest-ever selling download and predicted this year’s Christmas number 1 is now a certainty.

Gennaro Castaldo from HMV said: “'Hallelujah' promises to be the biggest 'X Factor' release yet, and the chances are that Alexandra will have the Christmas No.1 single in the bag even before her CD single officially hits the stores in midweek.”

“Alexandra’s biggest challenge for the festive top spot is likely to come from Peter Kay’s alter-ego Geraldine McQueen, but the reality is that while he may sell in the tens of thousands, Alexandra will sell in the hundreds of thousands - it’s really all about the race for the No.2 spot now.”

Bookmakers William Hill and Ladbrokes agree, and have both made her clear favourite to top the chart this Christmas with her cover of Leonard Cohen’s 'Hallelujah'. Burke’s chances were rated as 1/8 by Ladbrokes, and 1/5 by Hill.

Ladbrokes spokesman Nick Weinberg said: “It’s as close to a certainty as you’re likely to find.”

And one politically powerful fan who will no doubt be adding to her single sales is none other than London Mayor Boris Johnson who said he will be writing to congratulate her on the win.

Johnson said: “It is wonderful to see a Londoner, and a fellow north Londoner at that, winning the X-Factor.

“I wish her the very best with her singing career and trust it will be the success she wishes and hopes for.”

However, the ecstatic winner has had little time to reflect on her achievements or what may be to come.

Burke has a packed week ahead of her, kicking off with a live appearance on GMTV this morning before another long day of media interviews and photo-shoots.

With over eight million votes cast in Saturday’s live show, she said: “I am in disbelief. I keep saying to my friends and family, ’This isn’t real’.

“I cannot believe it’s happened, but I am so happy. This is the best feeling ever.”

She added: “I want to do a duet with Girls Aloud. That will happen I guarantee it.”

Head judge Simon Cowell described her debut single, a cover of a Leonard Cohen song, as “incredible”.

The CD single will be released on Wednesday, December 17.