O2

O2 UK redirects here. For other uses, see O2 (disambiguation). Telefónica UK Limited File:O2 logo. svgThe typographical O2 logo (2002-present)Type Private limited companyIndustry TelecommunicationsInternet Service ProviderFinancial servicesPredecessor Cellnet (July 1999)BT Cellnet (November 2002)Founded 1985Founder(s) John CarringtonHeadquarters Slough, Berkshire, United KingdomArea served United KingdomKey people Ronan DunneRamon RosDerek McManusRevenue File:Increase2. svg £2.973 billion (2010)Employees 10,147 (2010)Parent TelefónicaWebsite www.o2. co. uk Telefónica UK Limited is a telecommunications, internet and financial services provider in the United Kingdom owned by Telefónica, forming part of its Telefónica Europe division. It is the second-largest mobile telecommunications provider in the United Kingdom and is headquartered in Slough. O2 was formed in 1985 as Cellnet, a 60:40 joint venture between BT Group and Securicor. In 1999 BT Group acquired Securicor's 40 percent share of Cellnet and the company was later rebranded as BT Cellnet. In June 2000 BT Cellnet launched the world’s first commercial General Packet Radio Service. BT Cellnet was rebranded as O2 in 2002, along with BT Group's mobile telecommunications businesses in Germany, Ireland and the Netherlands. In 2005 it was announced that the Spanish telecommunications company Telefónica had agreed to acquire BT Group's European mobile telecommunications businesses for £18 billion as part of the company's expansion in the European communications market. As part of the terms of the acquisition Telefónica agreed to retain the O2 brand and the company's UK headquarters.