Telefonica UK Limited,[1] trading as O2 UK (stylised as O2), is a British telecommunications services provider.[3] It is the second largest mobile network in the United Kingdom behind VodafoneThree, with approximately 22.4million subscribers as of December 2025.[4] The name derives from the oxygen molecule.
Since 2021, O2 UK has formed a subsidiary of Virgin Media O2, a 50:50 joint venture between Telefónica and Liberty Global formed through the merger of their respective O2 UK and Virgin Media businesses.
The network was launched in 1985 as Cellnet, a joint venture between British Telecom (60%) and Securicor (40%), and later rebranded BT Cellnet following BT's acquisition of Securicor's share. Cellnet was one of the two original cellular network operators in the UK, alongside Vodafone. In 2001, BT spun off its BT Wireless division as mmO2 plc (later O2 plc), with the UK network adopting the O2 brand in 2002. O2 plc was acquired by Spanish telecommunications firm Telefónica in 2006.
History
Overview
The company was formed in 1983 as Telecom Securicor Cellular Radio Limited,[5] a 60:40 joint venture between British Telecom and Securicor led by John Carrington. It launched the Cellnet network on 7 January 1985, six days after the launch of Vodafone.[6] In 1999, BT acquired Securicor's share of Cellnet and the company was later rebranded as BT Cellnet.[7] In June 2000, BT Cellnet launched the world's first commercial General Packet Radio Service (GPRS) service.[8] The company, together with BT Group's mobile telecommunications businesses in Germany, Ireland and the Netherlands, was part of the BT Wireless division.
Network
BT Cellnet launched the world's first GPRS network on 22 June 2000, although GPRS-enabled devices were uncommon at that time.[40]
O2 publicly announced on 15 December 2009 that it had successfully demonstrated a 4G connection using LTE technology installed in six masts in Slough.[41] The technology, which was supplied by Huawei, achieved a peak downlink rate of 150 Mbps.[42]
In January 2012, the company announced plans to provide free internet to millions of residents and visitors in central London, by launching Europe's largest free Wi-Fi zone, along with free Wi-Fi access for anyone on any network in and around every O2 retail store.[43]
On 20 February 2013, Ofcom announced that O2 had been awarded spectrum in the 800 MHz band for 4G LTE coverage, bidding around £550 million for the spectrum.
Former operations
Fixed line and broadband
Alongside mobile telephone services, the company also provided fixed line services and home broadband.
O2 purchased Be Un Limited, an internet service provider in the UK, for £50 million in June 2006.[50] O2 retained the Be brand, and launched a separate O2-branded broadband service on 15 October 2007, using the Be network.
O2 announced in June 2011 a fibre optic broadband service designed to compete with the BT Infinity product, using FTTC technology.[51]
BSkyB agreed on 1 March 2013 to buy the fixed telephone line and broadband business of Telefonica UK, trading under the O2 and Be brands. The company agreed to pay £180 million initially, followed by a further £20 million after all customers had been transferred to Sky's existing business. The sale was subject to regulatory approval in April 2013,[52]
Marketing
Branding
The BT Cellnet consumer brand was renamed O2 – the chemical symbol for an oxygen molecule – as were all the group's other businesses (other than Manx Telecom). The rebranding was overseen by the Lambie-Nairn design agency, which developed the idea of the company supplying services that were essential, much the same as oxygen is essential for life. The company logo and associated graphics were designed using air bubbles to present this concept. The bubbles were photographed by London-based photographer Jonathan Knowles.[57] In 2002, O2 used Leftfield's dance track "Release the Pressure" in their ads.[58]
O2 adopted the slogan "See what you can do" in 2002 after the company's demerger from BT. In April 2008, the slogan changed to "We’re better, connected".[59] In July 2013 the slogan changed to "Be more dog",[60]
Environmental record
In February 2009, O2 became the first mobile telecommunications provider to be certified with the Carbon Trust Standard in recognition of its commitment to reduce its carbon footprint. O2 attained the standard after saving 47,000tonnes of carbon over the previous three years through its energy efficiency measures, including a £1.4million distribution of smart metering technology across the company's cell sites, offices and retail stores, and upgrades to more energy efficient systems across its mobile phone network. In addition to distributing energy efficient LED lighting and boiler system controls, the company was also able to reduce energy use by removing air conditioning units from some of its cell sites and reducing computer monitor standby times.[68]
O2 was a voluntary participant in the 10:10 climate change campaign, which required participants to cut their carbon emissions by 10 per cent by the end of 2010, and since broadened its approach to include a range of projects focused on carbon reduction and renewable energy.[69]
It was reported that in 2019, O2 achieved recertification from the Carbon Trust Standard for supply chain, at level 3, the highest level possible.[70]
External links
References
- TELEFONICA UK LIMITED overview - Find and update company information - GOV.UK^
- Telefónica 2017 Integrated Annual Report, Key Figures Telefónica, 2017^
- Contact us, O₂ corporate website. Retrieved: 6 December 2012.^