O2 is the commercial brand of Telefónica UK Limited and is a leading digital communications company with the highest customer satisfaction for any mobile provider according to Ofcom. With over 23 million customers, O2 runs 2G, 3G and 4G networks across the UK, as well as operating O2 Wifi and owning half of Tesco Mobile. O2 has over 450 retail stores and sponsors The O2, O2 Academy venues and the England rugby team.