Telefónica O2 is one of the largest providers of telecommunication services and broadband internet access in the United Kingdom, with over 20 million customers in this country. In Britain the company was launched in 1985 and it has been operating under the brand name O2 since 2001.

It is a leading company in non-voice services, but it is also known as a company which was first to launch GPRS network in England in 2000. O2 renders broadband service to customers who need very fast broadband and unlimited downloads. Apart from these, O2 offer includes pay monthly packages and deals with PAYG SIM cards. The company offers a lot of additional benefits for its clients. For example, O2 users can get a priority to buy tickets for some cultural events. O2 has an excellent coverage in the UK. The company's mobile network covers 99% and its 3G network over 80% of the UK population.

Next well-known characteristic of O2 is its involvement in environmental campaigns. O2 is an environmentally-friendly network. It is the first mobile telecommunications provider which got a certificate of the Carbon Trust Standard because it has made continuous effort to reduce its carbon footprint. In order to reduce energy consumption, O2 introduced more energy efficient systems across its network as well as removed air conditioning units from some of its cells and distributed energy efficient LED lighting.