In 1901, the Postmaster General and the NTC signed an agreement to prevent unnecessary duplication of plant and wasteful competition in London. In 1905, the Postmaster General and the NTC signed a further agreement for the purchase of the NTC's system on the expiry of its licence on 31 December 1911, an option for the Post Office that formed a part of the original licence agreement of 1881. On 31 December 1911 the NTC ceased to formally trade. The Postmaster General took over the NTC and its telephone systems and the NTC passed into liquidation. The National Telephone Company also issued stamps in various values to enable the public to pre pay for telephone calls made from company premises. Historical documents Records of the National Telephone Company (51 boxes, 8 volumes), c.1880s–c.1946 are held by BT Archives. See also Timeline of telephone companies in Birmingham, England Sir William Quilter, 1st Baronet Sources Hold the Line Please - The Story of the Hello Girls, Sally Southall, Records of the National Telephone Company, BT Archives (reference TPF) External links BT Archives official site BT Archives online catalogue Edison Companies website Bob Estreich's website: The National Telephone Company of Britain British companies established in 1881 Defunct telecommunications companies of the United Kingdom Archives in the London Borough of Camden Business and industry archives Alexander Graham Bell British companies disestablished in 1911 Telecommunications companies established in 1881 Telecommunications companies disestablished in 1911 1881 establishments in England 1911 disestablishments in England