O2's history spans over four decades — from the UK's very first mobile phone call in 1985 to the launch of satellite-to-mobile coverage in 2026. Here is the full timeline:
1 January 1985
Cellnet — a joint venture between British Telecom and Securicor — makes the UK's first ever commercial mobile phone call. The call is placed from London. The network operates on analogue 1G TACS technology, initially covering only major UK cities.
1985–1993
Cellnet expands 1G coverage across the UK, competing with Vodafone (the only other analogue operator). Mobile phones remain expensive, brick-sized devices used primarily by business professionals.
1994
Digital 2G GSM network launched alongside the analogue service. BT acquires Securicor's stake — network operates fully as BT Cellnet. 2G brings clearer calls, basic SMS text messaging, and vastly improved battery life.
1999
BT Cellnet wins a 3G spectrum licence at auction. The licence costs approximately £4.03 billion — a significant investment that shapes BT's mobile strategy for the following decade.
2001–02
BT demerges its mobile division. BT Cellnet rebrands as O2, becoming part of mmO2 plc — now trading independently on the London Stock Exchange. The O2 brand — clean, modern, distinctive — launches simultaneously across UK, Germany and Ireland.
2005
Telefónica SA (Spain) acquires O2 plc for £17.7 billion — one of the largest telecoms acquisitions in European history. O2 becomes a subsidiary of Telefónica Europe, alongside O2 Germany and O2 Ireland.
2007
O2 wins exclusive UK rights to sell the original Apple iPhone — a deal brokered directly with Steve Jobs. The exclusivity transforms O2's subscriber demographic, attracting younger, higher-spending customers and boosting brand cachet significantly.
2010–11
O2 launches LTE 4G trials. O2 Priority launches — a loyalty programme offering weekly treats and early event ticket access. Becomes one of the most used mobile loyalty programmes in the UK.
2013
O2 launches commercial 4G LTE — several months after EE. Covers major UK cities at launch, expanding to 98%+ outdoor coverage by 2016.
2016
EU regulators block CK Hutchison's (Three) £10.25bn bid to acquire O2 UK — ruling it would damage competition and harm consumers. O2 remains independent.
2018
O2 Refresh model launches — splitting device payment from airtime into two transparent, separate agreements on one bill. A genuinely consumer-friendly innovation not adopted at scale by any other UK MNO.
July 2018 ⚠️
Major outage: O2's 4G data service fails for approximately 32 million customers for around 24 hours — caused by an expired software certificate in a core network component supplied by Ericsson. One of the UK's largest telecoms incidents. O2 compensates affected customers.
2021
Virgin Media and O2 merge — Virgin Media O2 (VMO2) joint venture formed between Telefónica UK and Liberty Global. 50/50 ownership. Combined entity serves approximately 46 million fixed and mobile customers. O2 mobile continues as a distinct, separate brand.
2022–24
O2 deploys 5G Standalone (SA) architecture — reaching approximately 70% of UK population across 450+ towns. Shared Rural Network (SRN) programme — jointly funded by all four MNOs and UK Government — extends 4G to previously unserved remote areas of England, Scotland, Wales and Northern Ireland.
2026
O2 launches the UK's first satellite-to-mobile service via a partnership with Starlink (SpaceX). Extends signal to rural and remote locations unreachable by any conventional terrestrial mast. No hardware changes required on compatible devices. Annual rise confirmed: fixed ÂŁ2.50/month each April.