The Metropolitan Police led the way in improving policing methods, and were then followed by other forces around the country.
Specialisation
The Metropolitan Police Service set up a plain clothes detective department in 1842. This was a significant development in methods of policing as their role was to:
investigate crimes
examine clues
take evidence from the scene
deal with witnesses and victims
As they were plain clothed they could go undercover to investigate crimes.
The Metropolitan Police set up the Criminal Investigation Department (CID) in 1878, and by 1883 there were 800 CID officers. In 1884 the Special Investigation Branch, known as Special Branch, was set up. These changes were mostly in response to the growing threat of terrorism at the time from groups such as the Irish Republican Brotherhood.