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 (Ireland) their bills on time in August 2008. The Advertising Standards Authority upheld complaints concerning advertisements by O2. In August 2010, O2 was warned by the telecoms watchdog, ComReg, that it could not move customers to online billing without their explicit agreement. In March 2011, O2 pleaded guilty to a breach of the Data Protection Act at the Dublin District Court. In March 2011, it was revealed that Denis O'Brien made payments to the Minister for Communications, Michael Lowry, to aid Esat Digifone's licence bid. O2 (Ireland) Telefónica Ireland was a broadband and telecommunications provider in Ireland that traded under the