3UK chief executive David Dyson has announced that they had ambitious plans to double the carrier's customer base from 5 million to 10 million over the next four years, but warned that any delay in the UK's 4G spectrum auction could hit its plans.

Dyson said that the company could face network problems in urban areas by the end of next year if it is not provided with more mobile spectrum. He said that the network would start getting congested next year unless new 4G mobile radio spectrum is issued.

He accused rival carriers Vodafone, O2 and Everything Everywhere of deliberately trying to delay the UK's biggest spectrum auction so far.

He explained that Vodafone, O2 and Everything Everywhere had been allowed to restructure some of their 2G networks to 3G. However, they won't have to pay the 3G licence fee, which could amount to £300 million, until after the auction, which is why these carriers are trying to delay the auction for as long as possible.

In a press briefing in London, David Dyson said, "There is a huge financial incentive for rival operators to delay the auction. We are worried that the other three will attempt to squeeze us out of the market."

The 4G spectrum auction is expected to raise approximately £4 billion, but it has been delayed due to complaints from the side of Vodafone, O2 and Everything Everywhere.