The United Kingdom of Great Britain and Northern Ireland is a constitutional monarchy, meaning that it is officially "ruled" by a monarch whose powers are controlled by constitutional law. In reality, the monarch is a powerless symbolic figurehead and the country is governed by its legislature: a Parliament made up by the House of Commons and the House of Lords. Although Britain has a parliamentary system and the Prime Minister, the de facto head of government, is supposed to simply be the executive of a ruling political party, some recent Prime Ministers, notably Margaret Thatcher and Tony Blair, have tended towards a "Presidential" executive style of rule. More concisely, the monarch is head of state while the prime minister is the head of government compared to a nation like the US wher