Consumers and businesses in Britain are unlikely to benefit from 4G networks until 2015, Ofcom has warned.

According to the regulator's Draft 2012/13 Annual Plan (pdf), next-generation mobile networks won't be "widely available" for another three years at least.

4G networks utilise the 800MHz and 2.6GHz radio spectrums, freed up by the switch-off of terrestrial television, to offer faster mobile broadband services, with speeds thought to be 'up to' as much as 100Mbps. 4G networks will also be able to cope with a greater capacity than existing 3G services, as use of mobile broadband increases.

The two chunks of spectrum will be auctioned off to the UK's mobile networks. The auction was originally scheduled to take place in September 2008 but has suffered repeated setbacks. Ofcom recently pushed the auction back to the end of 2012, following the threat of legal action by O2, which claimed auction was illegal under EU law.

Ofcom’s proposal states that Vodafone and O2 already own part of the 900MHz spectrum, so a minimum amount of new 800MHz spectrum should be reserved for rival operators. However, O2 argues that the two different frequencies aren't directly comparable, describing the proposed spectrum floors as “a state aid”.

O2′s concerns have been backed up by Vodafone, which points out that Ofcom, in its desire to protect the UK’s smallest operator - Three - is inadvertently guaranteeing spectrum at 800MHz for Everything Everywhere, which it claims already has plenty of spectrum to run LTE. Both Vodafone and O2 say that all operators should start with a clean slate.

Meanwhile, Everything Everywhere, which is now the UK’s largest mobile operator following the merger of Orange and T-Mobile UK, has voiced its own concerns that the auction will favour Vodafone and O2. And Three UK has warned that Ofcom’s plans to re-farm 900MHz spectrum for 3G services could reduce competition by delaying LTE, and forcing Three to close.

Ofcom is continuing to claim it will hold the auction for the 800Mhz and 2.6Ghz spectrums in the 2012-2013 financial year, although this is subject to clearing the spectrums and ensuring the services that use the 800Mhz band are moved to another spectrum.

Mobile networks including O2 and Orange are already trialling 4G networks in the UK. Everything Everywhere recently teamed up with BT and Huawei to test Long Term Evolution (LTE) 4G technology in Cornwall. The technology has been touted as a way to deliver broadband to rural areas of the country, and help close the so-called “digital divide”.

Sophie Curtis contributed to this report