Quote Originally Posted by rory_20_uk View Post
Can two leaders both petition the queen to be PM? What happens then?

The constitutional position is that whilst Parliament is dissolved, ministers stay appointed. That includes the Prime Minister. Regardless of the result of the election, he continues in office until replaced by the will of Parliament or dismissed by Her Majesty.

Convention dictates that a Prime Minister whose party has lost an election decisively, and therefore will be definitively voted out once Parliament sits, stands down immediately. Not to do so would cause a constitutional crisis resolved only by the Queen dismissing him. However, if a sitting Prime Minister thinks he can form a government from whatever has been presented as a Parliament, he has the right to try. The monarch may, on advice, invite him to try or ask him to stand down because the mandate of the people clearly indicates a different desire. She would be unlikely to do the latter, but may give him only a few days, even hours (since if the will of the electorate were that clear, one assumes it would have expressed through the ballot box).

If he fails, Her Majesty would invite another leader to try and form a government. This not by petition - it is the monarch's prerogative, though convention dictates that she would choose the leader of the biggest (but in this scenario, still minority) party. If that leader then fails to form a government (remember, this is a government that will not be brought down by the first vote in the newly constituted Parliament) she may invite some one else, but in this case, the sitting Prime Minister (yes, he's still there unless dismissed) would either wait till Parliament voted him out on the first day, or call another election.