According to the Telegraph:
Despite lacking formal police training, hundreds of civilians have been made part of the “extended police family” by the Home Office under little-known legislation.
They have not been asked to wear any special uniforms to identify themselves, but must wear only a badge that can be as small as 73mm x 80mm.
It’s difficult to know where to begin. Perhaps with the English Bill of Rights of 1689, which promised “freedom from fines and forfeitures without trial”. Or perhaps with this dramatic article.