What is Paper Office?

Legal Definition
In English law. An ancient office in the palace of Whitehall, where all the public writings, matters of state and council, proclamations, letters, intelligences, negotiations of the queen's ministers abroad. and generally all the papers and dispatches that pass through the offices of the secretaries of state, are deposited. Also an office or room in the court of queen's bench where the records belonging to that court are deposited; sometimes called "paper-mill." Wharton.
-- Black's Law Dictionary
Legal Definition
An English office where state papers are kept.
-- Ballentine's Law Dictionary