PMR446 is basically the description of the band used by the cheap walkie-talkies that you can buy online and from Argos.
They are frequently used by children, campers, and by people too cheap to go for a business license (Wetherspoons and Argos spring to mind).
The regulations say that thay have a maximum power output of 0.5 watts, and have to have an integral aerial. Usually they are line-of-sight range.
Not that people take any notice of the regulations.
Analogue PMR Frequencies