Potential WiMax operators in Britain have until 16 January to register for the UK's biggest ever release of radio spectrum - because it is spectrum that new operators need if they are to launch services.

The regulator, Ofcom, has called for interested bidders to apply by 16 January, to join the auction for two bands of spectrum around 2.6GHz, originally set aside to expand 3G services. Under Ofcom's new "technology neutral" policy, the spectrum can be used for fixed and mobile WiMax services, and its auction has been keenly awaited. The final auction will take place between June and August 2008.

BT has already thrown its hat in the ring a year ago, saying it is very interested, and more recently a consortium led by Nortel and Urban Wimax is demonstrating the abilities of WiMax, specifically to encourage other operators to bid.

The two bands, at 2010-2025MHz and 2500-2690MHz, make up a bigger chunk of spectrum than the spectrum that mobile operators bought for £22.5 billion for 3G, way back in 2000. However, Ofcom expects to get significantly less money this time round. WiMax operators fear that mobile operators will bid the price up to limit competition, or that other businesses will buy the spectrum licences - which can be traded - speculatively.

This release of 190MHz of spectrum is actually the start, with around 400MHz coming under the hammer over the next few years, although the next big release won't be till analogue TV transmissions are switched off in 2012, allowing the so-called "digital dividend", and again benefiting services like WiMax, with spectrum around 600 and 800MHz, which gives very good indoor coverage.

Ofcom is also planning to auction spectrum around 900MHz, re-allocating part of the 2G band to new services, but with legal hurdles and the current incumbents Vodafone and O2 to deal with, this won't happen till 2009.