The GPO, Post Office Telephones and British Telecom (BT)

During most of the Cold War period, landline communications was a state monopoly, which meant the G.P.O. and its successors had a vital role to play in the UK's defence. This topic only covers projects for Civilian Government and not the many Military Communications projects running at the same time.

The Company History

At the start of the Cold War the General Post Office (GPO) operated all UK telecommunications. The GPO was a Government ministry with its finances strictly controlled by the treasury. The Engineering Department was engaged in lots of 'non-core' business and research. These included development of NHS Hearing Aids, High reliability valves and then transistors as components for undersea cable amplifiers. Designing, building and exporting highly stable quartz crystal oscillators all over the world. Various computer projects and even baggage handling at London Heathrow.
In the same way as the GPO Engineers designed and built the Colossus code breaking machine in WW2, they continued to design and build or advise on many military and civilian projects during the cold war period. Examples being the nuclear early warning system, a calculator for early radar stations to convert bearing and range of a target to a map reference and callout systems for firemen.
On October 1st, 1969 the General Post Office ceased to be a government department and became a public corporation. The Corporation was split into two divisions - Posts and Telecommunications - which thus became distinct businesses for the first time. The letter and parcel business became Royal Mail and the telecommunications arm became Post Office Telephones.
On October 1st, 1981 the British Telecommunications Act separated the services of the Post Office and Post Office Telephones became the public corporation British Telecom (BT). It was also at this time that the first steps were taken to introduce competition into the United Kingdom telecommunications industry: British Telecom lost its monopoly of the supply of customer premises equipment and the Secretary of State for Trade and Industry was empowered to grant licences to operators other than British Telecom to provide network and value added services. In 1982, Mercury Communications Ltd was licensed as the main competitor to British Telecom.
The Government privatised BT whilst still retaining a controlling share in the new company. The transfer to British Telecommunications plc from British Telecom as a statutory corporation of its business, its property, its rights and liabilities took place on 6 August 1984.

The Public Telecommunications Environment

In the sixties and early seventies the UK telecommunications infrastructure was very different from today's modern networks. Telephones were a luxury item with less than 50% of households owning one. All telephones were fixed landlines with a handful of very costly vehicle based mobiles operating around major cities. The network was exclusively run by the Post Office. As a Government department the Post Office had been starved of money by the exchequer. There were long waiting lists and a shortage of lines forced many people to accept party lines. Two houses would share the same wires to the exchange in a party line. Although they had different numbers there was no privacy between parties. The lack of lines between exchanges meant users would encounter the engaged signal and there were even television adverts discouraging the use of the telephone.
Although some large companies had their own internal telephone systems they were forced to rent BT lines to connect between offices. These lines were known as a Private Wire ( PW ) or a Private Circuit in the U.K. or as a 'Leased Line' in some countries. This gave the renter exclusive use of these wires provided to their premises by BT. As a government department along with their monopoly, it was obvious the GPO / BT would provide all landline based Military and Civil Defence communications too. Television pictures were carried on BT cables or microwave links from studios to transmitter sites.
It was not until 1982 that other companies were allowed to provide telephone services. Mercury Communications were the first to provide an alternative. They provided the backbone for many of the emerging cable television companies who began to provide business and residential telephone lines in the area they cabled. The Mercury network only connected major centres in a figure of eight and was very reliant on BT to deliver the final leg to the customer. As this wasn't a truly independent network, the majority if not all the civil defence communications remained in BT's hands.
The new competitors aimed to cream off the profitable business customers in towns and cities, and were very successful at this. They showed no interest in customers in villages close to large towns. In more rural areas, such as the highlands of Wales and Scotland, BT was burdened with providing and maintaining service to remote locations


Over the years, BT and its predecessors the GPO and Post Office Telephones have taken a huge beating from various TV programmes for its poor service to ordinary customers, but that that was really undeserved, because it was committed to massive works for the government, but could not say anything due to their 'Secret' classification of the projects. Additionally, when the GPO Telephones was a government ministry, the exchequer starved it of the monies needed for public telephone service improvements.
In the section below are some of the home defence systems that the G.P.O. / P.O. Telephones / British Telecom were responsible for providing and maintaining. Click on the link to the topic on this website. Additionally beyond the scope of this website, there were many large projects for all three U.K. armed services, Airforce, Army and Navy plus NATO.
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