O2 (UK) first commercial General Packet Radio Service. BT Cellnet, together with BT Group's mobile telecommunications businesses in Germany, Ireland and the Netherlands, was part of the BT Wireless division. This was spun off from the BT Group in 2002 to form a new holding company, mmO2 plc, which introduced the new "O2" brand for the businesses. In 2005, mmO2 plc was renamed O2 plc. O2 plc was purchased by the Spanish telecommunications company Telefónica in 2006 for £18 billion. Under the terms of the acquisition, Telefónica agreed to retain the "O2" brand and the company's UK headquarters. O2 plc became Telefónica
O2 (UK) certified with the Carbon Trust Standard in recognition of its commitment to reduce its carbon footprint. O2 attained the standard after saving 47,000 tonnes of carbon over the previous three years through its energy efficiency measures, including a £1.4 million distribution of smart metering technology across the company's cell sites, offices and retail stores, and upgrades to more energy efficient systems across its mobile phone network. In addition to distributing energy efficient LED lighting and boiler system controls, the company was also able to reduce energy use by removing air conditioning units from some of its cell sites and reducing