Ofcom has thrown a sop to the other mobile operators trapped in the slow lane behind EE's 4G network, by allowing them to build competing networks using existing spectrum they own.

Last year Ofcom allowed EE - which owns the Orange and T-Mobile brands in the UK - to roll-out the UK's first 4G network using 3G spectrum it already owned.

The decision angered other operators who were gearing up for the 4G spectrum auction this spring, which EE also took part in. They feared EE would gain a march on them, which it has.

Having said that those operators were also accused of dragging their feet about the terms of the 4G auction, and once EE was given the green light they suddenly settled down and accepted Ofcom's auction terms.

All the major operators won new 4G spectrum, but before they have been able to offer services, EE says it already offers 4G to over 55 percent of the UK population.

None of the other operators have announced firm 4G roll-out dates, but following Ofcom's decision to allow them to use existing 2G and 3G spectrum they own to launch 4G coverage, they now have an opportunity to cut some costs in doing it.

Matthew Howett, an analyst at Ovum, said: "Ofcom's decision to liberalise the 900MHz, 1800MHz and 2.1GHz bands for 4G mobile services will on the whole be welcomed by operators, and is fully in-line with other countries' and Ofcom's commitment to removing the previous command and control approach to spectrum policy."

Howett added: "The spectrum recently auctioned by Ofcom will most likely be used for Vodafone's, O2's and Three's initial deployment of 4G services though. EE was only able to refarm its 1800MHz spectrum and launch 4G services in this band given its large and contiguous spectrum holding."

Howett said the other operators would first have to move or clear parts of the existing spectrum they hold of existing 2G and 3G services - refarm it - before using that spectrum for 4G. EE had more room in its spectrum holding to quickly roll-out its 4G services.