Standard Telephones and Cables Ltd (later STC plc) was a British manufacturer of telephone, telegraph, radio, telecommunications, cables and related equipment. The company originated in 1883 an agent for the US Western Electric company that also had a factory in Antwerp, Belgium. The London operation sold US-designed telephones and exchanges to fledgling British telephone companies.

In 1898 the company acquired a failing cable factory at North Woolwich. In 1910 a private company formed: Western-Electric Co. In WWI the company contributed to the war effort in military communications and throughout the 1920s they became closely involved in radio. With its competitors, the company set up the British Broadcasting Company (later Corporation) as well as producing wireless receivers. In 1925 Western Electric’s international (i.e. outside USA) operations were purchased by a surprise buyer, the infant International Telephone and Telegraph Corporation which had been founded by Sosthenes Behn less than 10 years previously, with an aggressive and thrusting reputation. To fit with its other worldwide operations, ITT renamed its new UK operation Standard Telephones and Cables.

During WWII significant military work was undertaken with many developments particularly aerial warfare: communications, radar, navigational aids, and especially OBOE. The 1950s were characterised by the establishment of television broadcasting. Technical milestones were numerous and were crowned by the coverage of Queen Elizabeth II's Coronation in 1953. The steady spread of TV transmission and availability over Britain very often used STC technology and equipment.

In 1961 the company was listed as a subsidiary of International Standard Electric Corporation of New York. Works at New Southgate, North Woolwich, Footscray, Newport (Monmouthshire), Harlow, Southampton, Paignton and Enfield. They acquired Submarine Cables Ltd from AEI in 1970, making STC the world leader in the field of submarine cables, and the sole United Kingdom manufacturer. By 1977 Production of cables at Woolwich and Greenwich ceased as part of a rationalisation programme; work transferred to Newport (Gwent) and Southampton.

With developments in computer technology influencing and stimulating telecoms, the buzzword of the late 1980s became “convergence”. This meant that specialised suppliers, adapted to the specific needs of the local market would dominate. ITT needed to raise cash to fund continued development of its telephone switching system (System 12) and sold off most of the rest of its shareholding in STC.

The remainder of the 1980s saw STC lose its way. An attempt to enter the mainframe computer market with a failing player, ICL, led to financial strains. By 1991, with an ageing workforce, production spread over too many expensive sites and no clear leadership-succession to its chairman, Sir Kenneth Corfield, STC was bought by Northern Telecom (Nortel).