The owner of T-Mobile and Orange is set to steal a march on its rivals after being given the go-ahead to launch superfast mobile internet.
Everything Everywhere has been told by regulator Ofcom that it can use some of its existing spectrum for 4G services from later this year - before the industry's auction of airwaves due to take place in 2013.
Rival Vodafone said it was shocked by Ofcom's decision but the regulator argued that allowing Everything's application to vary its existing licence was in the best interests of consumers.
Ofcom's auction, which is due to start later this year, will give access to the fourth generation, or 4G, network, to at least 98% of people across the UK, enabling users to download data - such as music and high-definition films - at much faster speeds.
The auction will offer the equivalent of three-quarters of the mobile spectrum currently in use - some 80% more than released in the 3G auction which took place in 2000.
Everything, which is the UK's largest operator with around 27 million customers, will be allowed to offer 4G services from September 11, although Ofcom said the timing will be a commercial decision for the company itself.
Everything said: "Consumers will soon be able to benefit from the much greater mobile speeds that 4G will deliver. 4G will drive investment, employment and innovation and we look forward to making it available later this year, delivering superfast mobile broadband to the UK."
It is expected that 4G will allow users to download an album in as little as 60 seconds or a movie in 10 minutes, compared with an hour or more for 3G.
Everything, which is joint owned by Deutsche Telekom and France Telecom, employs more than 15,000 people and operates over 720 retail stores in the UK.
It declined to confirm reports that it will replace the Orange and T-Mobile brands from next March.
Thomas Wehmeier, principal analyst at Informa Telecoms & Media, said Ofcom's decision was a "major milestone" for the UK mobile market and vindication of Everything's decision to invest in readying the ground for 4G.
He added: "Everything now has a golden opportunity to establish an early lead in the UK's 4G market, but it will only be able to exploit this window if it is able to build a successful launch strategy.
"The most successful 4G operators globally, including in the world's most advanced 4G markets of the United States and Korea, have been those that came out of the traps quickly and built their networks out extensively."
He said a critical task will be to convince device manufacturers to build smartphones for Everything's network.
Mr Wehmeier said: "You can build the network, but without the right devices the customers cannot and will not come."