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) UK. The deal was subject to regulatory approval. The European Commission decided in December 2015 not to refer Hutchison's takeover of Telefónica's O2 business in the UK to the country's Competition and Markets Authority, which had asked to be allowed to investigate the planned acquisition, arguing that as the British competition regulator, it – and not the Commission – should have the right to rule on the 'transaction', which it argued 'threatens to affect significantly competition in the UK retail mobile and wholesale mobile markets', claiming that its investigation of the takeover would 'avoid duplication and fragmentation'. On 11 May