O2 (UK) 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 Securicor's share of Cellnet and the company was later rebranded as BT Cellnet. In June 2000, BT Cellnet launched the world's
Downe Communications controlling interest in the company to Charter for approximately $9 million in 1978. The company name was changed to Charter Data Services (CDS). Downe Communications Downe Communications was a publishing company founded by Edward Downe, Jr. that produced several popular magazines and provided subscription fulfillment services from 1967 to 1978. Downe was a trained journalist who worked at newspapers before becoming a magazine editor. In 1966, Downe purchased Family Magazine, a newspaper insert similar to Parade Magazine. He founded Downe Communications the following year. The company acquired the Ladies' Home Journal and The American Home in 1968 from Curtis Publishing