O2 was formed in 1985 under the name Cellnet, a joint venture between BT Group and Securicar. However, when BT bought out its partner’s share it was rebranded as BT Cellnet. This name remained until 2002 when they partnered with other BT telecom business in Germany, Ireland and Netherlands to form a new holding group under the name mmO2. Based in Slough, they have led the way in their field as well as offering travel insurance, broadband, and more. They launched the world’s first GPRS network in 2000 and demonstrated 4G connection in 2009. In 2012, furthermore, O2 announced plans to provide residents and visitors of Central London with free wi-fi. It will be the largest free wi-fi zone.
Handset: 4444(Free from sim)