Vodafone has failed to meet its 3G coverage obligations the communications watchdog Ofcom has said.
The assessment follows a 2010 Government directive that said mobile networks with 3G spectrum must cover 90 per cent of populated areas in the UK. Networks were given until 30 June 2013 to comply.
Thee, O2 and EE were found to have reached the coverage obligation by Ofcom, but Vodafone fell short by 1.4 per cent.
When mobile spectrum licences were awarded in 2000, networks were initially obliged to cover 80 per cent of the population, a rule that stayed in place for a decade until Ofcom were asked to raise the bar by Government.
Following the assessment, Vodafone has put in place a plan to comply with the 90 per cent obligation by the end of the year, Ofcom said. The measures will involve rolling out 3G to more mobile masts than Vodafone had originally estimated as being necessary.
As the firm has promised to reach the target by the 2014, the regulator has decided that no action will be taken against Vodafone at this time, pending a review in January.
Ofcom added that 4G will play a key role in delivering an initiative to delivering near universal mobile broadband coverage within the next few years.
"By 2017 at the latest, O2 is required to extend 4G coverage into indoor areas in which at least 98 per cent of the UK population lives. This is expected to cover more than 99 per cent of the UK population when outdoors," Ofcom said in a statement.
"Other mobile operators have also indicated that they intend to match this coverage. This will help to extend mobile broadband coverage into many parts of the UK that are still underserved by 3G."
As well as assessing coverage, Ofcom is soon to carry out extensive 3G and 4G speed test designed to help consumers decide which network operator to sign with. The findings will be published in spring 2014.