These documents, formerly in the Post Office Archives, cover the years 1870-1876. They relate primarily to the efforts of the Automatic Telegraph Co. to persuade the telegraph department of the British Post Office to adopt its system of automatic telegraphy, which was invented by George Little and subsequently improved by Edison. Many of the letters deal with tests conducted by Edison in 1873 to demonstrate the capabilities of the system to British telegraph officials. Among the correspondents for the Post Office are Spencer Cavendish (Lord Hartington), postmaster general in 1870; Richard S. Culley, engineer-in-chief for telegraphs; J. W. Eames and David Lumsden, staff members who monitored the tests; Henry Fischer, controller (financial officer) of the central telegraph office in London; Sir Lyon Playfair, a noted chemist who served as postmaster general in 1873; and Frank I. Scudamore, secretary in charge of the telegraph department. Other correspondents include Edison; George Little; George Harrington, president of the Automatic Telegraph Co.; Daniel H. Craig, the company's principal promoter; George E. Gouraud, a company agent who became a close Edison associate; and Sir James Anderson, a prominent British telegraph entrepreneur.

The BT Archives also contains manuscript and printed documents relating to the Edison Telephone Co. of London, Ltd., and its successors, the United Telephone Co. and the National Telephone Co.; to royalties for the use of Edison's quadruplex telegraph apparatus; and to the Electric Lighting Bill of 1882. A list of collections can be obtained by searching for "Edison" in the "Any Text" box of their online catalogue.