The BBC will launch five new high-definition channels by early 2014 and plans to launch further regional variants for its two current high-definition networks. The announcement comes after the national communications regulator Ofcom awarded transmission company Arqiva an interim licence to use spectrum released through the move to digital television. That could enable a further expansion of high-definition channels available through digital terrestrial television, extending the appeal of the free-to-air platform.

BBC One and BBC Two will be joined by BBC three and Four in high definition, together with children’s channels CBBC and CBeebies and BBC News.

“BBC One HD and BBC Two HD have already proved to be highly valued by our audiences and I’m delighted that we’re able to follow this with the launch of five new subscription-free BBC HD channels by early 2014,” said Tony Hall, the director general of the BBC. “These new channels will allow us to showcase more of our programming at its very best.”

The BBC says over half the homes in the United Kingdom now have high-definition screens. The number is estimated to reach over 80% by 2016 and 90% by 2019.

The high-definition channels will all be subscription-free, available through digital terrestrial television and on satellite, and will also be offered to all digital television platforms that carry high-definition channels. The majority of HD programmes from these channels will also be available to watch on demand through the BBC iPlayer.

The high-definition versions of BBC Three and CBBC will use capacity on the existing BBC HD multiplex, which covers 98.5% of homes in the United Kingdom. The HD versions of BBC Four, CBeebies and BBC News will use new capacity, which will cover part of the United Kingdom and grow in coverage over time.

There will be capacity for up to eight further high-definition channels for commercial broadcasters, which have yet to announce their plans.

The interim multiplex licences run until 2026, with a minimum term to the end of 2018, subject to revocation with notice of 24 months.

As with the other high-definition channels on digital terrestrial television in the United Kingdom, they will be broadcast using the DVB-T2 and MPEG-4 standards, which are together more than four times as efficient as their DVB-T and MPEG-2 predecessors, which are still used for standard definition.

Ofcom has made terrestrial capacity available using spectrum released through the switch to digital television.

It has awarded the licence to run the new multiplexes to Arqiva, the only applicant.

Under the Communications Act 2008, Ofcom has a duty to further the interests of citizens and the interests of consumers where appropriate by promoting competition. Ofcom is also required to secure the optimal use of spectrum.

The remaining spectrum released through digital switchover was auctioned off for 4G mobile services, raising over £2.3 billion, a significant sum, although rather less than the £22 billion paid for 3G services in 2000.

Ofcom simply awarded the spectrum for the high definition channels to Arqiva as it was the only applicant and met the statutory requirements. It is not clear whether the BBC will pay Arqiva for the use of the spectrum or simply for the provision of transmission services.

Ofcom previously determined to reserve the 600MHz band for digital terrestrial television. This could potentially allow the 700MHz band, currently used for digital television, to be released for mobile broadband services in the future, although not before 2018.

While the addition of more high-definition channels will extend the appeal of free-to-air digital terrestrial television in the short term, it seems likely that there will be a further shakeup of spectrum around 2018. By then, there could be enough high-definition receivers to enable a move to more efficient standards or even cease some standard-definition services, releasing more spectrum for mobile broadband.

In the longer term, the question will be whether to go beyond current standards for high-definition television and adopt yet another compression scheme, or indeed whether people will still be watching television through a rooftop aerial.