Privy Counsellors are members of the Queen's own Council, the 'Privy Council'. There are about 500 members who have reached high public office. Membership includes all members of the Cabinet, past and present, the Speaker, the leaders of all major political parties, Archbishops and various senior judges as well as other senior public figures. Their role is to advise the Queen in carrying out her duties as Monarch. In the past Privy Counsellors were the chief governing body and fulfilled the role that the Cabinet performs today.
During debates in the Commons, MPs who are Privy Counsellors are referred to by their colleagues as`The Right Honourable Member'.
Further information on this subject and a list of members of the Privy Council can be found from the following link.