The X Factor winner’s single ‘The Climb’ - originally by Miley Cyrus - sold 160,000 copies in the last seven days.

The track is now on course to become one of the biggest selling singles of 2009, with total sales of around 650,000 copies.

Rage Against The Machine’s ‘Killing In The Name’ fell one place to number two after topping the festive chart last week following a Facebook campaign.

Official Charts Company managing director Martin Talbot said: "The race for Christmas number one was the most exciting many of us can remember – but, having secured his own number one, McElderry can top his year off with another honour and has an excellent chance of making the year-end Top Five by next week."

Lady GaGa’s ‘Poker Face’ is the biggest selling single of the year so far, with sales of around 870,000 copies.

Fifth place is currently held by ‘In For The Kill’ by La Roux, which has sold 660,000 copies.

Meanwhile, Michael Buble's ‘Crazy Love’ replaced Susan Boyle's ‘I Dreamed A Dream’ at the top of the album chart.

The records exchanged places at the countdown’s summit, with Boyle’s effort falling to number two.

According to the Official Charts Company, ‘I Dreamed A Dream’ is now the biggest selling album of 2009.

(by Jason Gregory)