The following was kindly supplied by Richard Whittle.
I was in the Force about ten years. When the first hand-held Pye radios came
in I tested the first, taking it to 'blind spots' in the city so the Home Office
radio guys could see where to put the masts.
In the mid-late 1950's the police motorbikes had large valve sets in long boxes
mounted behind a single seat.
In the early 60's, when small valves were introduced, the sets became smaller.
Our force had them mounted in the petrol tank, kept the long pillion seats and
had an aerial right on the back, above the rear light. We couldn't get on them
by swinging a leg over or we'd hit the aerial.
In about 1969 some of the police cars in Bristol were fitted with fax machines.
