Virgin Media Limited is a British telecommunications company which provides telephone, television and internet services in the United Kingdom. Its headquarters are at Green Park in Reading, England. It is owned by Virgin Media O2, a 50:50 joint venture between Liberty Global and Telefónica. Since its foundation in 2007, the company has used the Virgin branding under license from Richard Branson.

Virgin Media owns and operates its own Hybrid fibre-coaxial (HFC) and Fibre to the Premises (FTTP) networks in the United Kingdom. Although most of the network is urban focused, the new joint venture, Nexfibre (a 50:50 joint venture between Virgin Media O2 and Infravia Capital Partners) is expanding the network to more areas which never had access to the Virgin Media network before. As of Q2 2023, it had a total of approximately 5.8 million customers. Since the acquisition of Smallworld Cable in 2014, Virgin Media is the main cable provider in the UK, with the exception of WightFibre on the Isle of Wight, and covers 51% of UK households. Virgin Media is one of the "big four" internet service providers in the UK along with BT (EE), Sky and TalkTalk. In the past, Virgin Media also operated a mobile virtual network operator (Virgin Mobile) and operated TV channels and produced television content (Virgin Media Television).

The company's origins lie in both Telewest and NTL, which merged in March 2006.

Telewest began in 1984 in Croydon under the name "Croydon Cable", and was acquired by United Cable of Denver in 1988. The company expanded during the 1990s and adopted the Telewest name in 1992 following the merger of its then-parent TCI and US West. It expanded into cable television access in 1999 by purchasing the remaining 50% stake in Cable London, one of the first cable TV companies in the UK, from NTL, adding 400,000 homes in north London. In April 2000 Telewest merged with Flextech, and in November extended its cable network with the acquisition of Eurobell, taking the total number of homes past 4.9 million.

NTL was established by Barclay Knapp and George Blumenthal in 1993 as "International CableTel", taking advantage of the deregulation of the UK cable market. Initially, Cabletel acquired local cable franchises covering Guildford, Northern Ireland and parts of Central Scotland and South Wales. In 1996, CableTel acquired National Transcommunications Limited (NTL), the privatised UK Independent Broadcasting Authority transmission network. In 1998 CableTel adopted "NTL" as its new name.

NTL purchased the ISP Virgin.net in 2004, having originally operated it as a joint venture with Virgin Group since it launched in November 1996. It sold ADSL broadband services through BT landlines to those living outside areas served by NTL's cable network and also offered subscription-based and subscription-free dial-up Internet access. Prior to acquiring Virgin.net, NTL offered a similar package called NTL Freedom.

Telewest and NTL began discussions about a merger in late 2003. Thanks to their geographically distinct areas, NTL and Telewest had co-operated previously, as in redirecting potential customers living outside their respective areas. On 3 October 2005, NTL announced a US$16 billion purchase of Telewest, to form one of the largest media companies in the UK. The merger agreement as structured would have required NTL to negotiate with BBC Worldwide (the BBC's commercial arm) due to a change-of-ownership clause written into the agreement for UKTV, a joint venture with Telewest's Flextech content division. To prevent this, Telewest instead acquired NTL.

In December 2005 NTL:Telewest and mobile virtual network operator (MVNO) Virgin Mobile UK announced that talks had taken place regarding a merger. Virgin Mobile's independent directors rejected the original bid of £817 million ($1.4 billion), taking the view that NTL's bid "undervalued the business". Sir Richard Branson reportedly expressed confidence that a restructured deal could go ahead, and in January 2006 NTL increased its offer to £961 million (372p per share). On 4 April 2006, NTL announced a £962.4 million recommended offer for Virgin Mobile. According to reports, Branson accepted a mix of shares and cash, making him a 10.7% shareholder of the combined company.