"Perfidious Albion" means:
- It is an Anglophobeic pejorative phrase used within the context of international relations and diplomacy to refer to alleged acts of diplomatic sleights, duplicity, treachery and hence infidelity (with respect to perceived promises made to or alliances formed with other nation states) by monarchs or governments of Britain (or England) in their pursuit of self-interest and the requirements of Realpolitik.
- Perfidious signifies one who does not keep his faith or word (from the Latin word "perfidia"), while Albion is a poetic name for Britain.