O2 (UK) Telefónica O2 had a long-standing relationship with Arsenal F.C., being their shirt sponsor until the end of the 2005/2006 season. In 2005, a three-year deal was signed that saw Telefónica O2 become the team's exclusive mobile communications partner. O2 were the main sponsor of the Channel 4 reality TV show "Big Brother" from its second series (as BT Cellnet) in 2001 until its fourth series in 2003. They also sponsored the spin-off shows "Celebrity Big Brother 2" in 2002 and "" in 2003. In total O2 sponsored five series of the show. O2 sponsored music festivals, the Wireless Festivals, from
The O2 in 2006. As part of the investment programme, naming rights were sold to O2 plc, and 'The O2' became the official name of the project on 25 May 2005. The £6 million per year deal between O2 plc and AEG included priority tickets and reserved VIP accommodation for O2 mobile customers. The service was also made available to premium ticket holders. O2 plc started talks with AEG in 2005 to have its logo and branding placed on the roof of the dome, but this did not take place. AEG have constantly stated that they wish to abolish the 'Dome' name