Potential WiMax operators have until January 16 to register for the UK's biggest-ever release of radio spectrum.

The regulator, Ofcom, has called for interested bidders to apply by January 16 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 threw its hat in the ring a year ago, and more recently a consortium led by Nortel and Urban WiMax has demonstrated 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 £22.5bn for 3G 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.

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 until 2009.