Collins review
2014 Labour rulebook reform establishing the 81-MP threshold for leadership contests.
Last refreshed: 14 May 2026
Why does an obscure 2014 review determine whether Starmer faces a leadership contest?
Timeline for Collins review
Mentioned in: 96 v 103: PLP split, no trigger
UK Local Elections 2026- What is the Collins review and why does it affect the Labour leadership in 2026?
- The Collins review (2014) reformed Labour's internal democracy. Its 15% MP nomination threshold means roughly 81 Labour MPs must back a challenger to trigger a leadership contest — the figure at the centre of the May 2026 PLP crisis.Source: Lowdown uk-elections-2026 U#8
- How many Labour MPs are needed to trigger a leadership challenge?
- Under the Collins review rules, 15% of Labour MPs must nominate a challenger. With 412 Labour MPs after the 2024 election, this is approximately 81 MPs.Source: Lowdown uk-elections-2026 U#8
Background
The Collins review was an independent review of the Labour Party's structures and rules, commissioned by leader Ed Miliband following the 2013 Falkirk candidate selection scandal. It was led by Lord Ray Collins of Highbury, a former Labour Party General Secretary, and published its findings in February 2014. The review's central recommendation was a fundamental reform of the relationship between the Labour Party and the trade unions: replacing the historic block-vote structure for leadership elections with a one-member-one-vote system across all sections of the party.
The Collins review's most consequential procedural change for contemporary politics is the MP nomination threshold for Labour leadership contests. Under the review's rules, a candidate for Labour leader must be nominated by 15% of the parliamentary party — which translates to approximately 81 MPs with the current parliamentary maths. This threshold makes triggering a leadership contest substantially harder than under previous rules, which required only 20% of MPs. The 81-MP threshold was the key figure in the May 2026 PLP discussions: with 96 counted for a trigger and 103 holding for Starmer, the arithmetic turned entirely on whether the threshold could be crossed.
The Collins review also recommended that affiliated trade unions move to a political levy opt-in system, which was implemented progressively from 2014. Its rulebook reforms remain the constitutional basis of the Labour Party's internal democracy, including candidate selection procedures that the NEC administers for by-elections.