A switchover from FM and mediumwave broadcasting to DAB Digital Radio should be undertaken by the end of 2015, the government has proposed.

In today's Digital Britain report, the government said that radio needs "its own, dedicated, digital platform – DAB – alongside the many other digital paths over which it can be carried" because it "is more than simply a stream of audio: it is an intimate, portable and ambient medium".

The report said that £200m would be needed to maintain the current FM network over the next 20 years, and that this would be better spent on investing in digital networks.

Under the "Digital Radio Upgrade" proposals, a switchover date would be announced at least two years in advance and only when at least 50% of listening is digital and when national DAB coverage is comparable to that achieved by the existing network of FM transmitters.

At that point, all services carried on local and national DAB multiplexes would turn off their analogue transmissions, with ultra-local services "consisting of small frlocal commercial stations and community stations" occupying the freed-up FM spectrum. Medium-wave stations not included in the DAB switchover would have the option of joining DAB or, if ultra-local, FM.

The government said that cash to spend on a concerted digital radio marketing push, and a build-out of the national DAB network, should come from the commercial sector - possibly from lowered transmission charges that are already in place - and the BBC, possibly in the shape of access to the digital switchover help scheme underspend.

"It is because we recognise that importance of radio to listeners that we believe the challenges of building a UK radio sector fit for a Digital Britain must be overcome," the report concluded. "We believe the proposals set out above will have a significant impact on setting and achieving radio’s future, particularly leading up to the Digital Radio Upgrade. However, whilst we can provide clarity of direction it must be for the broadcasters, manufacturers and transmission providers to deliver digital radio as a compelling proposition for listeners."