Ofcom has published maps of 3G mobile coverage from the major UK providers for the first time, with O2 and Vodafone lagging some way behind their competitors.

The telecoms watchdog said that mobile phone subscriptions in the UK now stand at over 76 million, exceeding the population of 60 million. Over two million new mobile broadband subscriptions were connected between February 2008 and February 2009 which, combined with the growing use of internet access from smartphones, shows the soaring demand for high capacity 3G access.

The 3G Coverage Maps (PDF) report clearly highlights the levels of 3G coverage across the UK offered by 3, O2, Orange, T-Mobile and Vodafone.

The maps were prepared in January and are based on computer-generated predictions used to establish the mobile operators' compliance with their 3G licence obligations.

Ofcom has stressed that the data reflected in the maps was collected to show general coverage rather than the precise availability or quality of mobile services. They are also based on outdoor coverage. Most operators have coverage indicators on their web sites which can usually drill down to much more local view.

The maps reveal that O2 and Vodafone are clearly lagging behind their competitors, which explains the network sharing deal announced between the two mobile operators in March.

Ofcom has pledged to assist the government with its proposals to make more spectrum available for mobile broadband and to improve 3G coverage on key transport routes.

The organisation has also promised to undertake new research into the technical quality of mobile broadband speeds, and look into the reasons why certain areas have consistently poor or zero reception.

Advisory organisation the Communications Consumer Panel welcomed Ofcom's new mobile coverage maps.

“Recent Panel research has shown that mobile coverage is an important issue for consumers – being able to communicate by phone and use mobile broadband on the move is increasingly important for social and work reasons," said Panel Chair, Anna Bradley.

"But there are a great many not-spots and areas where the quality of coverage is poor. This is reinforced by the coverage maps Ofcom has now published which show substantial gaps in mobile broadband coverage.”