The War Office Sub-centre despatch room, London, 1925.
Pneumatic messaging blows cylinders carriers inside tubes and was developed in London in the 1850’s as a way to handle the growing number of messages arrived by telegraph, a novel invention at the time.
Pneumatic tubes (or telegraph tubes) saved cost and time. They did not require skilled, well-paid telegraph operators, and they avoided mistakes often occurred during re-transmission. This tubes were used not only inside big buildings but also between telegraph stations, or linking central telegraph offices to main banks, companies, newspapers or government buildings. Also cash, documents and other small objects could be sent securely.
In the 1870’s the London system grew steadily. By 1891 over 32 million telegrams a year were being sent world-wide. Half of which were sent in the United Kingdom. By 1909, Pneumatic messaging in London handled 50.000 telegrams a day.
Even after the arrival of telephone lines, Pneumatic messaging kept its importance. Some government pneumatic tubes in London may still be in service today, as they are secure, virtually unjammable, and not susceptible to electronic piracy or electro-magnetic interference.