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
O2 (UK) every O2 retail store. On 20 February 2013, Ofcom announced that O2 had been awarded spectrum in the 800 MHz band for 4G LTE coverage, bidding around £550 million for the spectrum. This spectrum came with a coverage obligation from Ofcom, and O2 is obliged to provide a mobile broadband service for indoor reception to at least 98 per cent of the UK population (expected to cover at least 99 per cent when outdoors) and at least 95 per cent of the population of each of the UK nations – England, Northern Ireland, Scotland and Wales – by the end