Record buyers go download 'Crazy' for new Number 1

Music industry insiders are predicting it will be the tune on everyone's lips this summer. "Crazy" by the pop collaboration Gnarls Barkley, is poised to make history tomorrow by becoming the first single to top the charts on the strength of download sales alone.

More than 16,000 copies of the track were downloaded from the internet between Monday and Friday this week, making it likely that "Crazy" will beat Morrissey's new single "You Have Killed Me" and the current number one, American singer Ne-Yo's "So Sick", to reach the top slot.

The catchy track is the beneficiary of a change in the rules that allows singles to rank in the top 40 even if they are available only as a download, as long as they are released on CD or vinyl within a week.

Gnarls Barkley is the name adopted by the musical partners Danger Mouse aka Brian Burton, who won a Grammy for producing the Gorillaz' Demon Days album and Cee-Lo Green, a former member and co-founder of the Goodie Mob, who has collaborated with Ludacris, Pharrell Williams and Outkast

"Crazy" has been circulating on the internet as an illegal download since autumn 2005. It has been used to promote DJ Zane Lowe's Radio 1 show and has also been played on the station by Jo Whiley and Pete Tong. NME hailed Burton as "the hottest hip-hop producer in the world", and Arena predicted "Crazy" would be "the biggest single in the first half of this year ... this year's 'Hey Ya'", a reference to Outkast's 2003 hit.

Internet downloads were included in the singles top 40 a year ago, but initially they counted only if the track also existed in physical format, not to discriminate against consumers who did not have access to digital technology.

But the huge take-up of portable music players, and the launch of more than 30 high-profile music download sites headed by Apple's iTunes, persuaded the record industry to change its mind.

Retailers hope the new system will get rid of the phenomenon that began in the 1990s of a single entering the chart at number one or number two, then quickly disappearing again.

They expect the more staggered process of releasing a song as a download first then as a CD or 12-inch will allow tracks to become slow burners, entering the chart at a low position before climbing into the top 10.

Ne-Yo entered the singles chart at number 18 when his song was available as a download, but shot up to number one when it was released in a physical format.

An HMV spokesman, Gennaro Castaldo, said: "If Gnarls Barkley go in at number one solely on the strength of their digital sales, it will make chart history and show legal downloads have truly come of age."

Gnarls Barkley's first album, St Elsewhere, is released on 24 April.