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This briefing also sets out the results of past leadership elections and how hte rules developed over time.

Rules for leadership elections are set out in Labour’s Rule Book, with Labour’s ruling national Executive Committee (NEC) responsible for setting exact timings and election procedures to be followed.

Timings are affected by whether Labour is in government or not. If the Labour leader is also Prime Minister and the leadership becomes vacant for any reason, the Cabinet, in consultation with the NEC, appoints one of its members to serve as Party leader until a ballot can be organised.

If Labour is in opposition and the leader’s role is vacant, the deputy leader automatically becomes Party leader, and the NEC will determine the timing of a leadership ballot.


When a vacancy arises, Labour Party leadership elections consist of two stages:

Stage 1 – Nominations

Candidates seeking to enter the leadership ballot must be an MP.

They must be nominated by 20% of fellow Labour MPs.

The current rules were last changed in 2021 when the Labour Conference agreed to raise the threshold for nominations from 10% to 20% of MPs.

To progress candidates must also be nominated by:

  • 5% of CLPs; or
  • At least three affiliates of the Labour Party (at least two must be trade unions) where the combined membership of nominating affiliates should be at least 5% of affiliated membership.

Affiliates are groups or organisations which have interests consistent with those of the Labour Party – they include trade unions, and co-operative and socialist societies.

The nomination stage for CLPs and affiliates was added after a review of the leadership election in 2018. In the 2020 election, the candidates had to secure the required level of support from fellow MPs before moving on to the next round of securing the required nominations from CLPs and affiliates.

Stage 2 – Ballot

Eligible members of the Party and affiliates for the leader using a preferential voting system. Each voter has one vote but may rank the candidates in order of preference by marking their ballot 1, 2, 3, etc. The first candidate to secure over 50% of the vote, using rounds of transfers of preferences if required, wins. If a candidate wins over 50% on first preference votes no transfers are required.

The rules for stage one are set out in chapter 4 of the Labour Party Rule Book. The precise rules on eligibility to vote in stage two of a leadership election are set out by the National Executive Committee (NEC).

Leadership challenges

Labour MPs cannot formally hold a vote of confidence in the leader. However, they may initiate a leadership challenge each year prior to the annual session of Party conference.

An MP wishing to challenge an incumbent leader must be supported by 20% of Labour MPs. If enough support is gathered to initiate a stage two membership ballot, the incumbent leader is automatically on the ballot paper, and they do not need to seek nominations from MPs.

Elections for the deputy leader of the party follow the same format.

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