UK regulator Ofcom has begun the process of allowing the country’s mobile operators to use their existing licences for 4G services regardless of spectrum band.

In a statement today, Ofcom has proposed to liberalise all mobile licences in the 900 MHz, 1800 MHz and 2100 MHz bands “to permit the deployment of 4G services.”

The move is in response to formal requests from mobile operators Vodafone and 3 UK to remove the “regulatory constraint” barring them from offering 4G using their existing licences – 900 MHz, 1800 MHz and 2100 MHz in the case of Vodafone and 2100 MHz in the case of 3.

Ofcom has already given permission for market-leader EE to use its existing 1800 MHz spectrum to launch the UK’s first commercial 4G service, a decision that angered rival operators forced to wait for fresh 4G auctions at 800 MHz and 2600 MHz.  Those auctions are currently underway.

The regulator says that liberalisation “will meet a long standing objective to liberalise all mobile licences so that there are no regulatory barriers to the deployment of the latest available mobile technology.”

The move is in line with regulatory efforts at a European level to open up 3G bands for 4G use.

Ofcom has also proposed to increase the maximum permitted base station transmit power in the 900MHz band by three decibels, as requested by Telefonica and Vodafone which hold 3G licences in this band.

Ofcom’s full proposals are published here. Its consultation period lasts from today until 29 March. A final decision will be published in Q2.