The telegraph started with a captive audience - the railway companies. Once the railway companies' needs were met, the telegraph entrepreneurs started looking for new markets to conquer.

The Great Western Railway linking London to Bristol was the brainchild of Isambard Kingdom Brunel, its chief engineer.
The first stretch opened in 1838 from London to Maidenhead, and it was along part of this stretch that the first commercial telegraph system was installed by Cooke and Wheatstone the next year. The line to Bristol was completed in 1841.
Brunel laid broad gauge track along the line, claiming that it was safer for new high speed trains designed by Daniel Gooch. Unfortunately, the different track gauge made it impossible for trains to transfer from one system to another.
By 1849 the system was extended to Exeter, Windsor, Basingstoke, Hungerford and Gloucester. The railway embraced a host of impressive bridges, cuttings and tunnels and an innovative (although not always successful) approach to railway engineering, which helped it become one of the largest networks in Britain.
The Exchange Telegraph Co. Ltd. (also known as EXTEL) was created in March 1872 specifically to distribute financial and business information from the Stock Exchange and other commercial markets direct to subscribers.
EXTEL established ticker tape telegraph machines in offices, gentlemen's clubs, banks etc. and provided a continuous stream of commercial information to them.
It introduced a parliamentary service in 1876, a general news service in 1879 and a legal service in 1891. The business was so successful that by 1906 they had opened ten other branches outside of London.
The company continued to grow and improve, becoming increasingly more efficient. It added a faster financial service in 1907 and began operating a worldwide news service in 1913, with a separate sports service included in the 1930s.