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) greet and direct visitors. Other smaller touches include changing the lighting, carpets and seats in the arena to the colour blue. The O2 Arena was the site of the artistic gymnastics events and medal rounds in basketball for the 2012 Summer Olympics. In February 2017, in a continuation of its agreement with AEG, the developers of the site, O2 announced that it had renewed its naming rights for a further ten years. Since 2008, O2 is partnered with Live Nation and the Academy Music Group, allowing O2 to rename the music venues. The partnership allows O2 to offer customers priority