British Telecom (BT) is the name used by the world’s oldest telecommunications company between 1980 and 1984.

The company's origins date back to the establishment of the first telecommunications companies in the United Kingdom. Among them was the first commercial telegraph service, the Electric Telegraph Company, introduced in 1846. As these companies amalgamated and were taken over or collapsed, the survivors were eventually transferred to state control under the Post Office. The telecommunications side of the organisation became known as Post Office Telecommunications.

In 1980 the organisation was again renamed, becoming British Telecom.

In 1982 the UK government announced its intention to privatise British Telecom. This decision was implemented on 6 August 1984, when the business became a privatised company, British Telecommunications plc - the forerunner of today’s global communications company, BT Group plc, which serves customers in 170 countries.