... don't we have a system for catching drink drivers in the UK like they have out here in New Zealand?
Over here they have random police "road blocks" (usually in the evening/night and around urban centres) which require you to take a breathaliser before passing through. All it takes is about 10 seconds while they hold a device near your mouth and ask you to say your name and address... so it is a minimal inconvenience.
It just strikes me as an incredibly sensible thing to do, they must check hundreds of cars a night this way and it doesn't rely on either a police car spotting someone driving a little wonky or breathalising the person after they have crashed into a tree, or worse some innocent person. The resources it requires are pretty minimal too, just a few orange cones and two police officers.
So, why don't we do it?