Is that something to do with toilets?
No. It's the formal advisory body to the Queen, made up of around 600 people (very few of whom actually attend its monthly meetings). Among them are all current and former Prime Ministers, Cabinet ministers and, normally, the Leader of the Opposition—more on which later. You've also got royals, judges and bishops in the mix. Its current "Lord President" is Chris Grayling, the leader of the House of Commons. Its job is to advise the monarch in carrying out their duties. In practice this is usually pretty workaday, including getting the Queen's approval for orders already approved elsewhere. It is also, however, the court of last appeal for UK dependencies and overseas territories.
Why should I care about this?
Because it has been at the centre of an ongoing political row. Before the republican Labour leader Jeremy Corbyn took the party leadership, there was speculation that he might not join. In the event, he is going to, but today he will miss the first meeting to which he was invited, citing prior commitments. The reason this bothers some people is that it raises questions about Corbyn's swearing-in to the council. As part of the normal swearing-in ceremony, you kneel before the Queen. Corbyn has refused to say whether he will do this, and today's decision puts us further from finding out the answer.
The Telegraph reports that Corbyn may never need to go through a swearing-in ceremony; using an instrument called an "Order in Council," he could have his membership approved in his absence, the paper says.
What's the problem for a republican?
Aside from the kneeling before the Queen bit, you can see why someone who's not a fan of the monarchy would be squeamish about joining the council. The oath you swear when joining includes a pledge that "you will not know or understand of any manner of thing to be attempted, done or spoken against Her Majesty’s Person, Honour, Crown or Dignity Royal." On the other hand, Corbyn couldn't have just sacked off membership without serious consequences. Among other things, you have to be on the Privy Council to be allowed to see many top-level security briefings which would be vital to the Leader of the Opposition's work.
How did the Privy Council come about?
With its roots in Norman times, the Privy Council is a hangover from the old council system by which the monarch once governed the kingdom. By the reign of Henry VII, the King's Council was the system used by the King or Queen to carry out their will. It was made up of the Privy Council, the prerogative courts of Chancery, Star Chamber, and High Commission, and lower local bodies. The council system was torn up in the various revolutions and constitutional crises of the 17th century, but the Privy Council was never abolished. Instead, it withered into relative irrelevance as the Monarch more and more often turned to the cabinet for political action and decision making.
