Info taken from this existing thread:
Liverpool Police were the first to use helmets and to be armed with a cutlass(1836-1886)
They were the first to be equipped with rubber soled boots for nite duty(1889)
The first ever strike by police in 1919.
The first juvenile court in the land was opened in Crosshall street.
The first to have 2 way communications.
The first force to use closed circuit tv.
Images courtesy of Liverpool City Library and the Records Office: