are bt and 02 the same company?
O2 was formed in 1985 as Cellnet, a 60:40 joint venture between BT Group and Securicor. In 1999, BT acquired Securicor's share of Cellnet and the company was later rebranded as BT Cellnet. ... O2 plc was purchased by the Spanish telecommunications company Telefónica in 2006 for £18 billion.