Appointment In modern times, much of the process involving prime ministerial appointments is informally governed by constitutional conventions and authoritative sources, like The Cabinet Manual, paragraphs 2.7 to 2.20 and 3.1 to 3.2. The prime minister is appointed by the monarch, through the exercise of the royal prerogative. In the past, the monarch has used personal choice to dismiss or appoint a prime minister (the last time being in 1834), but it is now the case that they should not be drawn into party politics. The prime minister "...holds that position by virtue of his or her ability to command the confidence of the House of Commons, which in turn commands the confidence of the electorate, as expressed through a general election." By convention, the prime minister is also an MP and is normally the leader of the political party that commands a majority in the House of Commons. Prime Minister's Office The Prime Minister's Office helps the prime minister to 'establish and deliver the government's overall strategy and policy priorities, and to communicate the government's policies to Parliament, the public and international audiences'. The Prime Minister's Office is formally part of the Cabinet Office, but the boundary between its work and that of the wider Cabinet Office can be unclear; the wider Cabinet Office might carry out very similar work. Peter Hennessy has claimed that this overall arrangement means there is in fact effectively a Prime Minister's Department, though it is not called this. Prime Minister's Questions Prime Minister's Questions is a constitutional convention, currently held as a single session every Wednesday at noon when the House of Commons is sitting, in which the prime minister answers questions from members of Parliament (MPs). The leader of the opposition usually asks the prime minister six questions, and the leader of the third-largest parliamentary party can ask two questions. It is an occasion when the prime minister appears regularly on live television and radio. The prime minister also appears before the Liaison Committee to answer questions about public policy. Security and transport The personal protection of the prime minister and former prime ministers is the responsibility of Protection Command within the Metropolitan Police Service. The fleet of Prime Ministerial Cars provides the prime minister with a number of security features as well as transport. The vehicles are driven by officers from this unit. Air transport for the prime minister is provided