Tell me if I'm wrong, but I think this is specific to Jarrow. It means and officious, bad-mannered person, little Hitler, is equivalent in Standard British English. The story from my dad is that Jarrow was the place where all probation coppers were sent to finish their training - I don't know if that was before or after the Northumbria police were established. So the town was infested with nervous, aggressive young people in uniform who didn't belong-Jarra.
There was also the phrase, half-a-polis, an insulting term for a park keeper or any official in uniform.
The first syllable in polis has a short vowel, like Polly, and the second is schwa + /s/ . [I'm buggered if I can remember the keyboard shortcuts I set ages ago for the IPA. Which is interesting in itself.]