The UK has the Department of Public Prosecutions, which is essentially a burueacratic monolith that applies probability of success to determine whether or not it will proceed with a case.
As do we. Of course, an individual prosecutor always makes the decision between proceeding with or dropping a case, and these decisions can be appealed to a "higher" prosecutor, who may decide to proceed with the case after all. Generally works quite well, but I always used to save all the cases I was going to axe for one day, because I knew I'd be getting whiney phone calls from people the whole next day - only cost me one day of work that way.
