The Parliamentary and Presidential system are two differing forms of political arrangements which serve as the edifice of the political structure in U.K. and U.S. respectively. The Parliamentary system is based on the idea of fusion rather than separation of power. There is no clear cut compartmentalization by a rigid line of demarcation and the executive remains accountable to the legislature and can even be voted out of power by the latter. In addition to this, the Prime Minister who is the part of the executive appoints his ministers who need to be necessarily a part of either of the houses of the legislature.