Rules regulating digital download sales and how they count for chart success will be changed from 1 January.

The Official Charts Company is relaxing its rules to make more downloads count toward chart success, reflecting the dominant position of downloads in the UK singles charts.

The new rules will mean album tracks, B-sides and catalogue tracks will be able to take chart success, even if the song is only available online. CD singles will be allowed to carry extra tracks and offer extended running times.

Until now, downloads only contributed to chart success in the week before a song was released on a CD and until two weeks after a release was deleted.

Downloads have helped increase UK single sales from 32.3 million in 2004 to 62.1 million in the first 51 weeks of 2006.

"This new ruling changes the nature of a single and puts the consumer in the driving seat," Steve Redmond, director of the UK Official Charts Company told the BBC. "Literally any track can be a hit - as long as it sells enough."