In Britain, Counsellors of State are senior members of the British royal family to whom Queen Elizabeth II delegates certain state functions and powers when she is abroad or unavailable.
Any two Counsellors of State may attend Privy Council meetings, sign state documents or receive the credentials of new ambassadors to the United Kingdom.
Currently, the Counsellors of State are the Duke of Edinburgh, the Prince of Wales, the Duke of York and Prince William of Wales.