London Telephone Co
of Donnington House, Norfolk St, Strand, London WC2
1886 The London company had a virtual monopoly of telegraphy in London but faced substantial criticism - it was suggested the National Company used a different approach which gave many large towns better telephonic systems that that in the capital.[1]. This presumably refers to the system operated by the Post Office which had acquired the London telegraph system in 1870.
1922 Charles Henry Prichard of Battersea and Joseph Mangles of the company patented a telephone transmitter[2]