The Privy Council
In spite of my love of all quirky legal things English, until recently I had not focused on the Privy Council. This ancient body advised the Crown before the modern Cabinet system began, but for lawyers its most interesting role was as the highest court for (some) appeals from British courts and for the colonies of the Empire. Couple of oddities worth pointing out:
1. For a time the Privy Council was the highest court for Canada and other former colonies. The notion of having a foreign body as a Supreme Court raises fascinating jurisprudential questions.
2. The Privy Council is still the highest court (at least for some cases) from New Zealand.
3. Privy Council opinions never have dissents (the opposite of the seriatim approach that long prevailed in other royal courts).