Rage Against the Machine and "X Factor" winner Joe McElderry are engaged in a fierce battle for the U.K. Christmas No. 1 single.

The Official Charts Company said that Rage Against the Machine's "Killing In the Name" (Sony Music Entertainment) started the week just ahead of Joe McElderry's cover of Miley Cyrus's "The Climb" (Syco/Sony Music Entertainment).

Sales to the end of Monday (Dec. 15) for this week show that the sales gap between the two singles is about 10% of the total for "Killing In the Name."

The winner of the race for the U.K. Christmas No. 1 will be revealed on Sunday (Dec. 20). Winners of "The X Factor" TV talent show have secured the previous four Christmas No. 1 singles in the U.K.

Rage Against the Machine is an unlikely contender thanks to an Internet campaign aimed at preventing another "X Factor" festive chart-topper. The show's judge and creator Simon Cowell has described the campaign as "stupid" and "cynical."

A physical release of "The Climb" will boost its prospects when it is issued on Wednesday (Dec. 16), following the digital release shortly after the Dec. 13 final of "The X Factor." On the iTunes U.K. sales chart at 12.30pm GMT, McElderry was No. 1, with Rage Against the Machine No. 2 and Lady Gaga No. 3 with "Bad Romance."

Bookmaker Ladbrokes is not taking bets on McElderry, but is offering odds of 1/15 on Rage Against the Machine having the U.K. Christmas No. 1.

The other contenders are: 3OH!3 featuring Katy Perry (6/1), current U.K. No. 1 single act Lady Gaga (6/1), George Michael (18/1), former No. 1 Peter Kay's All Star Band (25/1), Robbie Williams (25/1), Susan Boyle (25/1), Leona Lewis (66/1), Mariah Carey (66/1) and Wham! (66/1).