History of telephone numbers in the United Kingdom

The telephone service in the United Kingdom was originally provided by private companies and local councils. But by 1912–13 all except the telephone service of Kingston upon Hull and Guernsey had been bought out by the Post Office. The Post Office also operated telephone services in Jersey until 1923 and the Isle of Man until 1969 when the islands took over responsibility for their own postal and telephone services – although the Isle of Man system remained part of British Telecom until 1987.

Post Office Telecommunications was reorganised in 1980–81 as British Telecommunications (British Telecom, or BT), and was the first major nationalised industry to be privatised by the Conservative government. The Hull Telephone Department was itself reconstituted as Kingston Communications, in 1987; it was sold by Hull City Council in the late 1990s and celebrated its centenary in 2004.

In November 1922 the General Post Office decided to adopt the Strowger system from the various systems it had tried and it was to include "Directors" in the exchanges in London. Demonstration models of the "Director" exchange were shown by manufacturer ATM of Liverpool as part of the Post Office exhibits at the British Empire Exhibition at Wembley in 1924 and 1925. However, it was not until 1927 that the first "Director" telephone exchange was brought into service in Holborn, London and rolled out progressively across Greater London. A 3 digit code, represented by letters, identified the local exchange. Director schemes were gradually introduced in the other major cities of the UK — Birmingham, Edinburgh (although a relatively small city, it obtained seven-figure dialling for political reasons), Glasgow, Liverpool and Manchester.

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