Secraphone Secure Phone

GPO / General Post OfficeGPO / General Post Office1660–1969The General Post Office (GPO) was the state postal system and telecommunications carrier of the United Kingdom until 1969. Established in England in the 17th century, the GPO was a state monopoly covering the dispatch of items from a specific sender to a specific receiver ; it was overseen by a Government minister, the Postmaster General. Over time its remit was extended to Scotland and Ireland, and across parts of the British Empire.Read more on Wikipedia → · British · Source: Science Museum Group (website)
Secraphone Secure Phone

About This Phone

Scrambler telephone handset for privacy unit (later known as Secraphone), c.1941, first developed for government and military use as a secure telephone system and issued by the General Post Office (GPO) in the UK around 1937. British Prime Minister Winston Churchill used this telephone system, later known as Secraphone, during the Second World War for secret communications within the British government and military. This scrambler telephone was first developed for government and military use as a secure telephone system and issued by the General Post Office (GPO) in the UK around 1937. This telephone set was used in combination with a large external box known as a privacy unit. The privacy unit used electronic circuits and radio valves to scramble outgoing telephone calls and unscramble incoming calls. Early privacy units suffered from reliability and security problems and could only deter a casual listener. The design was improved and made more secure later in the war.