Former prime minister Rishi Sunak has announced that he will be stepping down as leader of the Conservative Party. The party will now need to choose a new leader. This explainer sets out the process of the party leadership contest.

How does the leadership election start? 

The executive of the 1922 Committee sets the rules for the first stage of the leadership election. The chair and executive of the committee were chosen by Conservative MPs on 10 July 2024. The new members of the committee must set and announce the rules for the next leadership election. The chair of the 1922 Committee will then set out the timetable for election, which is then approved by the party board. The committee will decide when the contest begins. 

If there are attempts to change the constitution of the party to change the rules over voting, then the start date will be delayed.

How will the election be run?

The Conservative Party constitution sets out key rules and stages for how leadership votes run. Candidates must be members of parliament, meaning MPs who recently lost their seat in the general election are ineligible. The number of MPs needed endorse a candidate for nomination is set by the 1922 committee. This has varied in previous elections. Nominees in the July-September 2022 contest required only 20 MPs to nominate them, whereas for the October 2022 leadership contest the requirement was increased to 100 nominations. 

Elections are required to follow two stages once nominations are made. First, Conservative MPs will vote until two candidates remain, then the party membership will vote on those two candidates to elect the leader. If only one candidate reaches the threshold of support to be nominated, as was the case when Sunak became prime minister, then there is no membership vote. Similarly, if one of the final two candidates drops out, as Andrea Leadsom did in 2016, then the members will not vote. The exact timings of these stages will be set by the 1922 committee at the start of the election who set the timetable. They could for example set a longer or shorter deadline for nominations and time period for members to vote which would vary the length of the campaign.

How long will it take to appoint a new leader?

Since the modern leadership rules were introduced in 1998, the time taken to appoint a new party leader has varied from between 214 and 4 days. The shorter periods have been when only one candidate has met the nomination threshold, as was the case in October 2022, or when a candidate drops out before the membership vote, as in 2016.

If, as expected, there are multiple candidates, or there are attempts by the party to change its rules, then a new Conservative leader will not be appointed before September. The 1922 committee could also delay setting the rules for the election until later in the year.

Can the rules for the election be changed?

While the timing of the election and the number of nominations needed can be changed at each contest by the 1922 committee, the other rules are much harder to change. If, as some have speculated, the party wished to remove the membership vote from the process, then the party would have to amend its constitution.

In order to do this, the board or executive of the 1922 committee would first have to initiate a proposal to change the constitution. There would then be a ballot on the proposal, at least 28 days after initiation. The members of the national Conservative Convention, MPs, and Conservative Peers would all be eligible to vote, and the proposal would only pass with at least 66% of the vote, and 50% turnout.

Attempts to change the constitution to remove the members vote failed in 2005, not meeting the required threshold. This also led to the longest period between a party leader announcing their resignation and a new leader taking the reins since the modern voting rules were introduced in 1998. Under these circumstances, changes to the constitution for this upcoming leadership election are unlikely.