In the UK licence plate readers (LPR in the USA) are known as Automatic Number Plate Readers (ANPR) and as the title implies we have a lot of them:
UK number plate monitoring one of the 'world's biggest surveillance systems'
Link:http://www.v3.co.uk/v3-uk/news/24371...llance-systems

Personally I am not shocked that the (publicly owned) system across the UK ANPR system currently has 8,300 ANPR cameras (mainly overt on main roads and motorways or inter-state) in use submitting 25-35 million ‘read’ records to the National ANPR Data Centre daily, but lacks any legal framework or governance.

What is odd is that a former senior UK CT police officer, now having oversight of surveillance cameras has spoken publicly asking why:https://www.gov.uk/government/speech...ing-university

He is also critical of:
In the UK our (police) database is touching 18m images made up of custody photos (The FBI has 51m). They include photos of people never charged, or others cleared of an offence.
ANPR was originally limited to the "Ring of Steel" around the City of London IRRC long ago when the IRA were bombing London. Their arrival on motorways was originally announced as a prelude to road charging, traffic control and more - not for policing. They have been added in most city centres and almost every port.

The publicly owned system can be supplemented by downloading imagery from the privately owned and to my knowledge not netwworked ANPR at petrol filling stations, let alone car parks or airports.