O2 (Ireland) BT Group and 1 mm02 share for each British Telecommunications share they held. After the de-merger, most of mmO2's operations, including Digifone, were rebranded O2. mmO2 plc later became O2 plc and remained an independent company until 2005. On 31 October 2005 it was announced that Telefónica, S.A., the Spanish telecommunications company, had made a recommended takeover bid for O Ireland's parent company, O2 plc. This was then approved by shareholders and O was officially purchased in mid February 2006. The O2 brand is now used in several countries for Telefónica's mobile operations outside Spain and Latin America, where Telefónica
The O2 sound and security technology, including RFID smart card tagging of staff and VIP guests, and digitally managed sound. There are four computer server rooms to provide this technology. The complex is also covered by CCTV and security personnel. Arena visitors and their bags are screened with X-ray machines and metal detectors at the main entrance. The O2 Arena (referred to as the North Greenwich Arena for the 2012 Summer Olympics and Paralympics) is a 20,000 capacity venue, primarily used for live music. It is located at the centre of The O2 and is the first American-style, multi-purpose arena in London.