Privy Council (UK) Until the eighteenth century, the chief source of executive power in the state. Now plays a much-diminished role, advising the Sovereign on Orders in Council, issue of Royal proclamations, etc. Headed by the Lord President of the Council, it consists of Cabinet ministers, Archbishops, Lord chief Justice, Master of the Rolls, Speaker of the Commons, etc. The whole Council is called together on the death of the Sovereign. The Judicial Committee of the Privy Council has appellate jurisdiction.