O2 (UK) BT subsidiaries: Esat Digifone in Ireland, Viag Interkom in Germany and Telfort Mobiel in the Netherlands. The rebranding was supported by a European advertising campaign, which began on 16 April 2002, across all four countries, at a cost of £130 million. The main launch campaign ran from 18 June and was developed by Vallance Carruthers Coleman Priest, working alongside brand consultancy Lambie-Nairn, creators of the "O2" brand identity. In March 2005, mmO2 restructured its shares and the company was relisted as O2 plc. On 30 November 2005, O2 agreed to a takeover by Telefónica, a Spanish telecommunications company, for £17.7
O2 (UK) of MVNO networks Tesco Mobile and Giffgaff. To apologise for this, O2 announced that it would be giving hundreds of thousands of its customers compensation for the issue. Pay monthly customers received a 10 per cent discount on their bill whereas Pay As You Go users received a 10 per cent refund on their first top up in September. On 24 November 2014, it was reported that BT were in talks to buy back O2, while at the same time BT confirmed that it was also in talks to buy EE. BT subsequently entered into exclusive talks with EE. On