The old beak
I am wondering where the phrase 'the old beak' or 'up before the beak' comes from. I am sure it relates to being sent before the magistrate (or judge) for some misdemeanour but cannot locate anything on it's meaning, history or the source.
'Beak' seems to be of unknown origin: it means not only a Magistrate, but also (formerly) a policeman and a schoolmaster (presumably by extension.)
DFG
My Collins dictionary says 'theives jargon. 19C'. This is certainly supported by my Classical Dictionary of the Vulgar Tongue, which gives DFG's definition of Judge, Policeman, etc.