Seven of the UK’s music download retailers have joined forces to help educate people about the growing availability of music in the MP3 format.

Digitalstores, 7digital, HMV, Play.com, Tesco Digital, Tunetribe and Woolworths Download will use a new 'MP3 compatible' logo on their sites.

The logo been created by the Entertainment Retailers Association (ERA), whose members account for more than 90 per cent of music, DVD and computer games sales in the UK.

The aim is to help show consumers that their MP3 downloads will play on all PCs and Macs and on nearly all digital music players, as well as help them identify legal download sites.

Figures from the Official UK Charts Company show that, in October, sales of single-track downloads were up 41 per cent on sales in October 2007. Sales of album downloads were up 69 per cent on sales a year previously.

Russel Coultart, ERA Digital chairman, said: “2008 has been the breakthrough year for legal MP3 downloads. We now want to take the message out to music fans that they can legally buy downloads which are not locked to specific players or computers or mobile phones.”

Ben Drury, chief executive of 7digital said: “The beauty of an MP3 file is that once you have bought it, you don’t need to be a computer genius or a lawyer to make it work and you are not locked into a relationship with a single retailer or hardware manufacturer.”

The MP3 compatible logo is expected to be adopted internationally. It is also supported by the UK record company trade association, the BPI.

Geoff Taylor, BPI chief executive, said: “Digital music is fast-moving and exciting, so initiatives that help consumer understanding are important. This logo will not only help give consumers confidence that the music files they are buying will play on a wide range of devices, but will also help them know that they are legal and that artists are getting paid.”