When we were younger defective lights was a sure way of being pulled over at night, not so much for the lack of lighting necessarily, but as an excuse for the police to check if the driver had been drinking.
After reading recently that in some areas police won't be attending burglary scenes of crime, unless somebody was injured, it makes me wonder how many police are available for this type of work.
But it's not limited to the UK with tales that the whole of Oregon (which is similar in size to the UK) sometimes manages with less than 50 police on duty across the whole state.