As predicted this week's singles charts was topped by Gnarls Barkley track 'Crazy'. Gnarls Barkley is a collaboration Danger Mouse (real name Brian Burton) and hip-hop artist Cee-Lo.

This has been a landmark in the changing face of music distrobution and become first single to get to number one in the charts on downloads alone. The physical product being available next week.

Recently introduced rules for a download to count in the official charts a single must be available to buy as a CD in the shops the following week.

The single has been a big hit after being used on the BBC's adverts to promote Zane Lowe's Radio 1 show. And has been released without Video Promo or any physical release.