Telecommuncations in the United Kingdom have evolved from the early days of the telegraph to modern broadband and mobile phone networks with Internet services. 

National Telephone Company (NTC) was a British telephone company from 1881 until 1911 which brought together smaller local companies in the early years of the telephone. Under the Telephone Transfer Act 1911 it was taken over by the General Post Office (GPO) in 1912. 

Until 1982, the main civil telecommunications system in the UK was a state monopoly known (since reorganisation in 1969) as Post Office Telecommunications. Broadcasting of radio and television was a duopoly of the BBC and Independent Broadcasting Authority (IBA): these two organisations controlled all broadcast services, and directly owned and operated the broadcast transmitter sites. Mobile phone and Internet services did not then exist. The civil telecoms monopoly ended when Mercury Communications arrived in 1983. The Post Office system evolved into British Telecom and was privatised in 1984. Broadcast transmitters, which belonged to the BBC and IBA, were privatised during the 1990s and now belong to Babcock International and Arqiva. 

British Rail Telecommunications was created in 1992 by British Rail (BR). It was the largest private telecoms network in Britain, consisting of 17,000 route kilometres of fibre optic and copper cable which connected every major city and town in the country and provided links to continental Europe through the Channel Tunnel. BR also operated its own national trunked radio network providing dedicated train-to-shore mobile communications, and in the early 1980s BR helped establish Mercury Communications’, now C&WC, core infrastructure by laying a resilient ‘figure-of-eight’ fibre optic network alongside Britain’s railway lines, spanning London, Bristol, Birmingham, Leeds and Manchester.
What communications system was in Britain prior to 1982?
Until 1982, the main civil telecommunications system in the UK was a state monopoly known (since reorganisation in 1969) as Post Office Telecommunications