Jeremy Corbyn has secured a significant victory after Labour’s ruling body agreed to proposed changes that will make it easier for a leftwing candidate to run for the party leadership.
The national executive committee accepted a compromise deal on the so-called McDonnell amendment, named after the shadow chancellor, John McDonnell, who is in favour of reducing the number of MPs needed to nominate a leadership candidate.
In a further strengthening of the left’s position, the party has also increased the number of NEC delegates from members and unions and authorised a further review of party rules to be conducted by Corbyn’s allies.
The proposed changes have been described as “tectonic” by some commentators because they mean that the parliamentary party will find it harder to stop a leftwing successor to 68-year-old Corbyn.
It could postpone indefinitely moves by some MPs who want to return Labour to policies pursued by Tony Blair and Gordon Brown.
The proposed changes went through at an NEC meeting in the party’s headquarters in central London that lasted more than four hours. They will be voted upon at the party’s annual conference in Brighton, which will open on Sunday.
Committee members approved a reduction of the threshold from 15% of MPs and MEPs to 10% in order to select candidates to be placed on a ballot for members, sources said. It does not go as far as the 5% demanded by some activists.
McDonnell tried to stand for the leadership in 2007 when he was a backbencher but was thwarted by a lack of nominations from parliamentary colleagues.
When Corbyn stood for the party leadership in 2015 he struggled to secure enough nominations, and only made it through to the membership ballot because some MPs said they would second him even though they disagreed with his views.
The 35-strong committee also discussed whether to add more members to the ruling body to represent trade unions and the party’s membership.
Sources said that the NEC agreed to add an additional three delegates to the current six to represent the party’s 600,000 members. Unions will be given an extra delegate.
The committee is currently finely balanced between pro- and anti-Corbyn delegates.
Key figures who have previously been seen as potential obstacles to reform by the leadership, such as the party’s deputy leader, Tom Watson, and Corbyn-sceptic unions, did not block the changes.
Some so-called moderates have been persuaded that the unexpectedly strong showing in the general election has given Corbyn the right to make changes to the party.
Party sources said that a deal was thrashed out before the NEC meeting, which has enabled Corbyn to gain more influence over the party machine without driving his critics out.
The committee has also authorised a review of the party’s structures that will open the way for further changes, such as to how the party selects MPs and forms policy.
The former Labour MP Katy Clark, an ally of Corbyn who is now the Labour leader’s political secretary, will lead a “party democracy review” to make the case for major changes to how the party elects leaders, selects MPs and forms policy. Clark’s review will report directly to Corbyn and the party chair, Ian Lavery.
The NEC also voted in favour of strengthening the party’s position on antisemitism, following claims that the party turned a blind eye to prejudices.
Some on the left will be disappointed that the party has held back from pushing for mandatory re-selection, which could have forced MPs to reapply for their positions before an election.
With the NEC’s backing, the changes are highly likely to pass a vote on the conference floor.
Commenting on the changes, Emma Rees, Momentum’s national organiser, said: “We welcome the review, which is a promising first step towards a 21st-century Labour party that empowers its members and is able to win elections.
“We’re glad that all wings of the party are finally recognising their invaluable contribution, and understand that it’s both right and strategic for members to have more of a say.”