Leonard Cohen's 'Hallelujah' could be the first single by the winner of this year's X Factor competition, according to reports.

The track, already performed on the show by contestant Diana Vickers, would be released in time to compete for the coveted Christmas number one spot.

But the decision is said to have angered other contestants on the show, who believe it would give an unfair advantage to Vickers.

"Tempers are running high. They feel it is just the latest in a series of stunts that have left them wondering if the competition has already been won,” a source told the Mirror newspaper.

"Simon (Cowell, X Factor judge) came out at a charity dinner saying his choice to win was Diana. And now they feel the winner's song has been chosen because it suits her vocals."

In recent years, the winner of The X Factor has been all but guaranteed the Christmas number one position as a result of the shows huge popularity.

(by Jason Gregory)