O2 (UK) they can do it too" in reference to Vodafone and EE, O2's biggest competitors and the UK's top three mobile-telecoms companies. O2 (UK) Telefónica UK Limited (trading as O2 – stylised as O) is a telecommunications services provider in the United Kingdom, owned by the Spanish multinational Telefónica, and is headquartered in Slough. With 25 million subscribers (as of December 2017), O2 is the second-largest mobile network operator in the United Kingdom after EE, with Vodafone in third place. O2 was formed in 1985 as Cellnet, a 60:40 joint venture between BT Group and Securicor. In 1999, BT Group acquired
O2 (UK) their inception in 2005 until 2008. O2 is the sponsor of The O2 in London. Since its launch in 2007 the Millennium Dome has been transformed and rebranded by O2 into an entertainment venue. O2 customers can get "Priority Tickets" up to 48 hours before they are released to the general public. The O2 offers exclusive areas for O2 customers, including the "blueroom" bar and the "O2 lounge". Once inside, O2 customers can change their experience of these areas by dictating the wallpaper designs and jukebox requests through text. O2 also contributed 'O2 angels', a team of people trained to