Idiom
be a ... through and throughbe a [Londoner/patriot/politician etc.] through and through
if someone is a Londoner etc. or is French etc. through and through, they behave in a way that is typical of such a person and that is the most important part of their character.He always managed to say the right thing. He was a politician through and through.She never really settled in England. She was French through and through.