Conservatives are the largest opposition party in the United Kingdom and form Her Majesty’s Loyal Opposition in the Parliament of the United Kingdom. The Conservative Party is the second largest political party in the United Kingdom in terms of sitting Members of Parliament, the largest in terms of public membership, the largest in terms of sitting councillors in local government, and the oldest political party in the United Kingdom. It is the most successful political party in British history in terms of election victories. The current party leader is David Cameron, who acts as the Leader of the Opposition and heads the Shadow Cabinet.