Mercury Communications was a national telephone company in the United Kingdom, formed in 1981 as a subsidiary of Cable & Wireless, to challenge the then-monopoly of British Telecom (BT).

In 1898, to break the near-monopoly held by NTC, the Postmaster General's office, which was in charge of licensing new telephone companies, issued thirteen new licences.

[1] Under the Telephone Transfer Act 1911, NTC was taken over by the GPO in 1912, and created a state-run monopoly that would run nearly all telecommunication assets in the UK for the next seventy years.

In 1981, Mercury Communications Ltd – a consortium of Cable & Wireless, Barclays, and BP – was founded as an experiment in telecommunications competition, primarily to compete with British Telecom.

[1] In 1989, Mercury formed a consortium with Motorola and Shaye Communications to run Callpoint, a Telepoint-based nationwide mobile phone service.

[8] PCNs were envisaged to be superior to the then-existent cellular phone technology, giving customers the flexibility to make or take calls in the home or car, in an aeroplane, or while on holiday.

Mercury forged strategic alliances with 16 UK cable companies, which enabled them to offer both telephone and television services to their customers.

The service was first rolled out in the London area bounded by the M25, and offered free mobile to landline calls at off-peak times, weekends and Bank Holidays.

Callers could use the 'Mercury 2300' service via their existing BT phone line by dialling a '131' prefix followed by a ten-digit customer code, then the number they wished to dial.

This enabled the Smart Box to be connected to a large number of TR's customers, so traffic was routed away from BT onto Mercury's network.