The Office of Fair Trading (OFT) has given Telefonica’s O2 and Vodafone the go-ahead to share network infrastructure in a deal first announced in June.

By creating a 'national grid' comprising 18,500 sites, the two operators will ensure they can offer 2G and 3G indoor coverage to 98 percent of the UK population by 2015, and the same coverage for LTE by 2017, as required by UK regulator Ofcom.

Referring to the OFT's approval of the deal, Vodafone UK CEO Guy Laurence said: “This is excellent news for British consumers, businesses and the wider economy."

The plans, which include the formation of a company called CTI Limited that will own and manage the infrastructure, were submitted to the OFT in August. The partnership does not include spectrum sharing, meaning the two companies will continue to compete in terms of products and services.

The CEOs of O2 UK and Vodafone UK said in June that the network-sharing plan will provide a “level playing field” for UK operators.

UK market-leader Everything Everywhere (EE) already has a network-sharing deal in place with its Orange UK and T-Mobile UK brands and 3UK in a JV known as Mobile Broadband Network Limited (MBNL).

In addition, EE will be able to offer LTE ahead of the 4G spectrum auction in 2013 as it has been given permission to repurpose 1800MHz spectrum it already holds.