O2 (UK) cent share of Cellnet for £3.15 billion. Cellnet had five million customers at the time of its acquisition. The company was later rebranded as BT Cellnet , and it became a part of BT Wireless, a group of companies owned by BT. BT announced on 3 September 2001 that the BT Wireless business would be spun off from the main group as a newly listed holding company, mmO2 plc, operating under the "O2" brand. Shareholders approved the plan at an extraordinary general meeting on 23 October 2001. BT Cellnet relaunched as "O2" on 18 June 2002, along with other former
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.