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
The O2 purchased by the mobile telephone provider O2 from its developers, Anschutz Entertainment Group (AEG), during the development of the district. AEG owns the long-term lease on the O2 Arena and surrounding leisure space. From the closure of the original "Millennium Experience" exhibition occupying the site, several ways of reusing the Millennium Dome's shell were proposed and then rejected. The renaming of the Dome in 2005 gave publicity to its transition into an entertainment district. The Dome's shell remained in situ, but its interior and the area around North Greenwich Station, the QE2 pier and the main entrance area were completely