The Prime Minister’s failure to secure a vote in favour of continued EU membership raises obvious questions about both his future and his Government’s. Can the Prime Minister be changed without a general election? And in what circumstances would an early election be possible?

Changing the Prime Minister independently of a general election is a straightforward matter — it happened, in decidedly less dramatic circumstances, when Gordon Brown took over from Tony Blair in 2007. Now that we know David Cameron is going to resign, the appointment of a new Prime Minister will be a matter for the Conservative Party and — formally, at least — the Queen. By constitutional convention (meaning long-established, but not legally binding, practice) the Queen invites to be Prime Minister the person best equipped to command a majority in the House of Commons. That usually means the leader of the party that has an overall majority following an election. If, however, a Prime Minister resigns during a Parliament — rather than following defeat in a general election — then who succeeds her or him is a matter for the governing party, as paragraph 2.18 of the Cabinet Manual makes clear. It will therefore be for the Conservative Party to determine who should succeed Cameron by electing a new leader under internal party rules.

A snap general election is a more complex matter, not least because of the Fixed-term Parliaments Act 2011 introduced by the Coalation Government. The default rule under the Act is that elections are held at five-yearly intervals, and only at those times. There are, however, two circumstances in which an early, or snap, election can be held. First, the Commons can deliberately trigger an early election if MPs representing two-thirds of all seats in the House support a motion in favour of an early election. That is a higher bar than the one that applied prior to the 2011 Act, when a vote of no confidence on a simple majority could form the precursor to an early election. Second, however, an early election is triggered under the Act if — on a simple majority — the Commons passes a motion that it “has no confidence” in the Government and then fails, within 14 days, to pass a motion saying that it does have confidence in the Government. The intention is that this creates a two-week window in which the existing Government can seek to regain the confidence of the House or in which other parties can negotiate so as to form an alternative administration. Only if that two-week process does not yield a viable Government is an election triggered.

The upshot, then, is that a snap election could be held, but only if either two thirds of MPs were in favour of it or if a simple majority expressed no confidence in the Government and, following the 14-day cooling-off period, there was no viable Government that could command the support of a majority of MPs. The bottom line, therefore, is that while early elections remain possible, the triggering of them is now regulated by the Act, making the holding of snap elections less straightforward than used to be the case.