Answer:
The United Kingdom Government
The monarch appoints a Prime Minister as the head of Her Majesty's Government in the United Kingdom, guided by the strict convention that the Prime Minister should be the member of the House of Commons most likely to be able to form a Government with the support of that House. In practice, this means that the leader of the political party with an absolute majority of seats in the House of Commons is chosen to be the Prime Minister. If no party has an absolute majority, the leader of the largest party is given the first opportunity to form a coalition. The Prime Minister then selects the other Ministers which make up the Government and act as political heads of the various Government Departments. About 20 of the most senior government ministers make up the Cabinet and approximately 100 ministers in total comprise the government (or something like that.)As in some other parliamentary systems of government (especially those based upon the Westminster System), the executive (called "the government") is drawn from and is answerable to Parliament - a successful vote of no confidence will force the government either to resign or to seek a parliamentary dissolution and a general election. In practice, members of parliament of all major parties are strictly controlled by whips who try to ensure they vote according to party policy. If the government has a large majority, then they are very unlikely to lose enough votes to be unable to pass legislation.
Constitution: Constitution of the United Kingdom
Leader: Prime Minister