Mobile users in the UK could get access to superfast mobile data services over new 4G signals this year after Ofcom approved a controversial proposal by Everything Everywhere.

The regulator has said that the request by Everything Everywhere - the joint venture of T-Mobile and Orange in the UK - to reuse its existing spectrum to launch 4G Long Term Evolution (LTE) services should be approved.

This means that 4G signals can be rolled out in Britain from September 11, although rival operators have expressed their "shock" at the move, particularly considering as it comes ahead of a major planned auction of 4G spectrum.

In a statement today, Ofcom said that it has approved an application by Everything Everywhere to use its existing 1800 MHz spectrum to deliver 4G services.

Despite previous criticism of the proposal, the regulator said that it would "deliver significant benefits to consumers", while there is "no material risk that those benefits will be outweighed by a distortion of competition".

Ofcom further believes that delaying the 4G launch to next year as in the auction proposal would "be to the detriment of consumers".

Varied licences have now been issued to Everything Everywhere enabling the firm, the largest UK mobile operator by customer base, to launch 4G LTE from September 11 over its 1800Mhz spectrum.

However, it will depend on when manufacturers can get handsets that are compatible with the new 4G signals to the market before customers can benefit.

4G can deliver superfast mobile data services of more than 70Mbps, suitable for advanced tasks such as video streaming and mobile gaming.

Ofcom said that its decision took into account the forthcoming release of additional spectrum in the 800Mhz (freed up after the digital TV switchover) and 2.6 GHz bands in a planned multi-billion pound auction getting underway later this year, which will see four UK operators granted 4G spectrum to launch services in 2013.

In 2011, Ofcom ruled that 2G spectrum could be used for 3G as part of plans to "liberalise spectrum use to the benefit of consumers". Today's ruling essentially permits 4G use over the 2G spectrum as well, with the intention of meeting the "growing demand from internet-connected devices such as smartphones and laptops".

However, Vodafone said that it was "frankly shocked" that Ofcom has reached the decision. The firm accused the regulator of showing a "careless disregard for the best interests of consumers, businesses and the wider economy".

Vodafone believes that Ofcom has "refused" to take into account the potential competitive distortion involved in allowing one operator "to run services before the ground has been laid for a fully competitive 4G market".

It feels that the move gives Everything Everywhere a "massive incentive" to attempt to delay the 4G auction with legal challenges to the detriment of rivals.

A spokesperson for Vodafone also noted that Ofcom's timing is "particularly bizarre" considering that Everything Everywhere is currently in talks to sell some its spectrum to Three, which would "fundamentally change" the balance of the 4G auction.

"Ofcom's timing is particularly bizarre given the reports that Everything Everywhere is currently in discussions to sell some of its spectrum to Three, which Ofcom has previously been at such pains to protect with its over-engineering of the 4G auction. This means the balance in the auction will fundamentally change," said the spokesperson.

"The regulator has spent several years refusing to carry out a fair and open auction. Now its decision today has granted the two most vociferous complainants during that entire process a massive incentive to further delay it.

"We wholeheartedly support the Secretary of State [Jeremy Hunt's] call for the 4G auction to occur in December and look to the regulator to finally do its job and produce a competitive market for 4G services as soon as possible.

"We firmly believe that a fully competitive market for 4G services is in the best interests of Britain. We have already committed ourselves to reach 98% of the UK population with indoor 4G services by 2015 - two years before Ofcom's own target - but we need to acquire spectrum in the auction to achieve this. Ironically, all that stands in our way right now is the regulator."

In its own statement, Everything Everywhere said: "Ofcom's decision to make 4G available this year is great news for the UK. Consumers will soon be able to benefit from the much greater mobile speeds that 4G will deliver.

Broadbandchoices.co.uk telecoms expert Dominic Baliszewski said that Ofcom's decision will be "great news" for Orange and T-Mobile customers as they will benefit first from the superfast and more reliable 4G services.

However, he noted that the lack of market competition could keep prices high, while there are other costs involved for people hoping to upgrade to 4G.

"Surprisingly, many UK handsets will not actually support 4G technology so customers may have to upgrade to a completely new handset, adding additional cost to the switch," said Baliszewski.

"Data also tends to be much more expensive to download over mobile networks too, with low download allowances and expensive penalties for exceeding these limits.

"As 4G opens the floodgates for downloading, customers will need to make sure they do not get stung with excess download fees."