The British system is a constitutional monarchy, characterized by the unity of the monarch and the parliament as the center. Constitutional monarchy greatly weakened the king's power and ended the feudal autocracy in Britain. The central government and its core cabinet are the highest state administrative organs. The cabinet is made up of political parties that have a majority in the parliament. After the parliamentary election, the king appointed the leader of the parliamentary majority as the prime minister, authorized him to form a cabinet, and approved the list of his cabinet members. Cabinet is the core of the government's leadership, and its core figure is the Prime Minister. By convention, the Prime Minister is also the Chief Finance Minister of the Cabinet. At the beginning of the cabinet, the prime minister was mostly a nobleman, and later he was mostly a member of parliament. For nearly a hundred years, it has become a common practice that the Prime Minister only comes from the House of Commons. The Prime Minister is not only the Chief Executive, but also the leader of the parliamentary majority party. He combines executive power and legislative power and controls the ruling power of the country.