Funny how radio was developed over the years, as it became more and more practical for everyday use up to the point where we are now. This article over at AE5X shows how the British police department first utilized radio for the "Bobbies" back in 1931. Although it wasnt very practical they were starting to see the potential of using radio for patrol duty. It was a tube transmitter/receiver that was carried on the belt loop with a 100ft wire wrapped around the helmet for the antenna. Although the article mentions a 100 mile radius, since it was wrapped around the helmet it couldnt have been more than 1-2 mile radius at best. Plus the added radiation from the radio that close to the bobbies head could cause serious brain damage. The effects were still unknown with the new technology.
You can read the original article with pictures HERE.