Universal, the world's largest record label, has said that it will still start offering music for download without copy protection in an attempt to increase digital sales.

The company, whose catalogue of artists includes U2, Amy Winehouse, and 50 Cent, said that in the next few months it will start to make tracks available without the software, known as digital rights management (DRM), which prevents owners copying songs.

The hope is that more customers will buy digital music if they have more control over songs once they are downloaded — such as the ability to transfer them to different media players, an option ruled out if a song file is protected by DRM.

Songs on CDs have no such protection. An attempt by Sony to introduce DRM on CDs two years ago was abandoned and the company agreed to compensate its customers for installing software on their computers without permission.

Universal said that it would offer the DRM-free tracks through a range of online music retailers, including RealNetworks, Wal-Mart and Amazon, until January, at which point it would assess the impact the move had on consumer demand, as well as piracy.

Absent from the list of partners was Apple's iTunes, with whom another label, EMI, struck a deal to sell DRM-free songs earlier this year.

DRM has been a source of great controversy in the music industry.

Record labels have traditionally insisted that the protection is necessary to prevent rampant copying of their music, but they also acknowledge that the system has handed Apple a significant degree of control in the music retail because of the ubiquity of the iPod.

Songs bought from the iTunes store cannot easily be played on other music players. Nor can other digital music stores, such as HMV, sell downloads to iPod owners.

Steve Jobs, Apple's chief executive, said in February that he would abandon DRM "in a heartbeat" if the labels agreed, prompting Edgar Bronfman, the chief executive of Warner Music, to reply that Mr Jobs’s argument was “completely without logic or merit”.

Both Warner and Sony BMG recognise, however, that if Universal changes its stance, they will be unable to persist with digital safeguards.

As of April, iTunes customers have been able to buy EMI songs without copy protection for 99p, 20p more than they would cost usually.

Univeral, which is increasingly reluctant to work with Apple, having refused to renew a long-term contract with the retailer last month, has opted instead to offer its DRM-free music on platforms other than iTunes, though the songs will be able to be played on iPods.

Under the new arrangements, first revealed in The Times in June, Universal will sell as least some tracks in unprotected form for 99 cents.

The digital music market nearly doubled in value last year, from $1.1 billion to $2 billion (£542 million to £985 million), but the growth has not compensated for the overall decline in CD sales, which have slumped globally by 23 per cent since 2000.