In the nineteenth century, the United Kingdom of Great Britain and Ireland had the world's first commercial telegraph company. British telegraphy dominated international telecommunications well into the twentieth. Telegraphy is the sending of textual messages by human operators using symbolic codes. Electrical telegraphy used conducting wires to send messages, often incorporating a telegram service to deliver the telegraphed communication from the telegraph office. This is distinct from optical telegraphy that preceded it and the radiotelegraphy that followed. Though Francis Ronalds first demonstrated a working telegraph over a substantial distance in 1816, he was unable to put it into practical use. Starting in 1836, William Fothergill Cooke, with the scientific assistance of Charles Wheatstone, developed the Cooke and Wheatstone telegraph. The needle telegraph instrument suggested by Wheatstone, the battery invented by John Frederic Daniell, and the relay invented by Edward Davy were important components of this system.

Cable & Wireless plc was a British telecommunications company. In the mid-1980s, it became the first company in the UK to offer an alternative telephone service to British Telecom. The company later offered cable TV to its customers, but it sold its cable assets to NTL in 2000. It remained a significant player in the UK telecoms market and in certain overseas markets, especially in the former British colonies of the Caribbean, where it was formerly the monopoly incumbent. It was also the main supplier of communication in the British South Atlantic, including Saint Helena and the Falkland Islands. It was listed on the London Stock Exchange and was a constituent of the FTSE 100 Index.