By Ben Gartside

This morning, Momentum director Jon Lansman resigned his position, and appointed Labour NEC member Christine Shawcroft in his place. However, it's unlikely to be Lansmans last role of the dice.

With the appointment of the universally liked Shawcroft, it plays into the idea that Lansman will be seeking election to the steering committee at the conference later this year, not only to give himself legitimacy as Momentum's de-facto leader, but also to legitimise his controversial constitutional changes.

Earlier this week, he brought sweeping changes to the organisation, seeing the data wing abolished, along with the national committee, the steering committee and the conference arrangements committee. Most controversial however is Momentum attempting to affiliate to the Labour party.

It would be unprecedented to see a factional group formally affiliated to Labour, which has strict rules governing what constitutes an affiliated socialist society.

The Labour party rule book says a group "having their own programme, principles and policy, or distinctive and separate propaganda, or possessing branches in the constituencies, or engaged in the promotion of parliamentary or local government candidates, or having allegiance to any political organisation situated abroad" would be ineligible for affiliation. This quite explicitly rules out Momentum with its current form.

Momentum’s constitution embodies the vision of our members, & enables us to focus on the Tories & helping Labour win #MomentumMovingForwards pic.twitter.com/5H4aPQF1QE — Momentum (@PeoplesMomentum) January 10, 2017

However, Lansman has taken steps to adhere to the rule book. Momentum's data arm has been dissolved, and regional organisers are expecting to lose Labour Party members who were canvassed in the leadership election but may not be Momentum members, in the next few days.

In order to to affiliate, Momentum would need to stop producing original content, shut down every local group based around constituencies or council wards, or any material not aimed at Labour party members exclusively, all of which are fundamental pillars of Momentum.

So, if the odds were stacked against affiliation, why has Lansman done this? There seem to be only two possible reasons. Either he feels he has enough of a left-majority on the NEC to override eligibility guidance from the compliance unit. Or he is hoping that a consequence of an application for affiliation would be an opportunity to purge many nuisances within Momentum who belong to left splinter groups, and who would no longer be applicable for membership. Many within Labour feel Lansman has lost patience with the far-left.

"It's understandable that Lansman has lost patience with the antics of AWL and other entryist groups and has opted for a constitution that excludes them," Luke Akehurst from Labour First says.

But according to Momentum activists, figures like Lansman have virtually no control over regional Momentum committees anyway. Many had never even encountered senior left figures before Corbyn's election, and removing powers of regional committees is only likely to consolidate Lansman's power.

Leading moderates are tentative about whether Momentum would be ruled out due to Clause II. The clause details the constitutional rules for party structures and affiliated groups, including in this case, what requirements are set for an affiliated group . "It would be completely inappropriate to allow a faction to formally affiliate to the party - it would institutionalise factionalism," Akehurst says.

Although Momentum seem to be ruled out explicitly by Clause II, it's worth remembering that many people thought Corbyn didn't have the right to automatically be on the 2016 leadership ballot, but due to the political balancing of the NEC, he made it on. Never say never.

Ben Gartside is a freelance writer and student at the University of Hull. You can follow him on Twitter here.

The opinions in politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners.