Channel 4 and the BBC will not allow Mac owners to use their video-on-demand services until Apple resolves digital rights management issues, vnunet.com has learned.

While Windows PC owners can use Channel 4's 4OD and the BBC's iPlayer services to watch TV programmes shown by the broadcasters, Mac users are prevented from using either. 

This is because TV bosses fear that they could fall foul of copyright issues, as Apple refuses to license its FairPlay DRM copy protection to third parties.

If the broadcasters allowed Mac users to access programmes they would be open to potential copyright abuse as they would have no DRM protection.

Apple has resolved some DRM issues with EMI in recent weeks, allowing Apple to start offering the record label's stable to its iTunes customers without FairPlay so that songs can be played on a range of devices.

But unless a similar deal can be hammered out, only owners of the very latest Macs, which are compatible with Windows copyright protection, will be allowed to use the service, said a Channel 4 spokeswoman.

Speaking at the Internet World show in London yesterday, Rod Henwood, new business director at Channel 4, and the man charged with running its video-on-demand service, confirmed that DRM was the reason why 4OD was unavailable to Mac owners.

"If Apple sorts out the DRM then it will be offered on Macs," he said, adding that, while Channel 4 is keen to sort out these issues, no resolution date is in sight.

Channel 4 launched its video-on-demand service late last year, becoming the first broadcaster actively to put all its home grown shows online.

The BBC and ITV are now following suit. But while ITV is showing programmes on its website, which means that the quality is slightly poorer, Channel 4 and the BBC require users to download an application.

Programmes can then be downloaded over the internet giving near DVD quality, or played on the site, which is much like watching a YouTube video.

Henwood admitted that broadcasters are walking into the unknown by offering TV online and accepted that, with so many people able to freely (but illegally) download TV programmes, in particular the latest US blockbusters, the 4OD model will have to evolve.

This could mean that it will have to hammer out deals with US programme makers to make some shows available online before they appear on Channel 4, and close to when they are broadcast by networks in America.

But Henwood said that Channel 4 would use its resources to establish its service rather than "restrict choice or waste time chasing after pirates and illegal sites" that make TV programmes available for download.

"The fact that catch up [on TV programmes shown on C4] is available for free means that there is no reason not to come to us," he said.

Apple did not respond to a request for comment by the time of going to press.