For all intents and purposes the setting is modern day Ireland. A man gets drunk in a bar, gets kicked out, wanders the streets mouthing off and generally being disruptive and gets picked up by a policeman. He doesn't have any ID on him, since he's a criminal of sorts but they don't know that. Will they need to take his details? He's not actually assaulted anyone or vandalised anything, so could they just throw him in a cell til morning and let him go when he's sober? Would they let him have a phone call, or just take a number off him and call his 'bailer-outer'?
Another thing, (sorry...) he has a young friend who comes to the police station to pick him up. Would they let him wait in the station all night, or send him back to the hotel? Would he be allowed to see his drunk friend and talk to him? And would they want his ID as well (young friend is also a criminal)?