Labour MPs have voted to kick off Jeremy Corbyn's private parliamentary secretary from the party's ruling national executive committee - but the battle for control of the NEC will continue. The parliamentary Labour party voted overwhelmingly to recognise the role of the leader's PPS as a frontbench position, with 188 MPs voting in favour of the motion.

But in reality the move will make little long-term difference to Corbyn's position on the party's NEC, where, thanks to the victory of Pauline McCarthy of the Bakers' Union at the expense of Community's representative, there is still a narrow pro-Corbyn majority on most issues. In this instance, many supporters of Corbyn, both in the parliamentary party and the wider membership privately recognise that the arrangement where the PPS to the party leader - who attends shadow cabinet meetings and cannot in practice vote against their leader on the NEC - didn't count as a frontbench position and therefore was able to continue acting as the backbench representative, was something of an anomaly. There is just one recorded instance of that happening before, in the final year of Gordon Brown's government, when Anne Snelgrove was Brown's PPS and backbench representative on the PLP, an arrangement that was only tolerated due to the proximity to the 2010 general election.

It may yet be that Labour's NEC asserts its belief that it should rule on the composition of the NEC, not the PLP. Labour's rule book is unclear which of the party rulebook or the PLP's standing orders should take primacy in instances such as these, and some pro-Corbynites believe that the NEC should strike down the attempt to remove Rotheram from the NEC.

The likelihood of that is reduced by other factors. Tensions are running high on the NEC at present. The Unison leadership believes that Corbyn and John McDonnell, the shadow chancellor, tried to increase support for Heather Wakefield, the defeated candidate for Unison's general secretaryship, who ran to the left of Dave Prentis, the incumbent. Allies of Corbyn and McDonnell, meanwhile, note the almost unremittingly hostile tone of Prentis' public pronouncements about the Labour leadership. Elsewhere, the two largest affiliated trade unions, Unite and the GMB, presently at loggerheads over a variety of issues, and both unions at variance with the leadership over Trident. The GMB is far more unabashedly pro-Trident than Unite, which combines both viscerally anti-nuclear elements with a significant number of workers in the defence industry, for whom any move to abolish Trident would be regarded as an outrage. The GMB and Unite are in direct competition for members over members in the defence industry and some in the GMB would welcome a more anti-Trident stance from Unite as they believe it would aid recruitment to the GMB.

Seperately, Jennie Formby, Unite's political director and regarded as Len McCluskey's closest ally, has angered some within the GMB by pushing through an attempt to strip security firm G4S of the contract for securing Labour party conference due to G4S work in the West Bank. The GMB is the recognised trade union of G4S and fears the action will lead to job losses. Others on the NEC are nervous that, as Labour can only choose a contractor from the government's list, ruling out G4S entirely would result in a bigger bill from Securicor, as "they'd be the only game in town", in the words of one NEC member.

That backdrop means unified action in favour of Rotheram against the PLP is highly unlikely to pass, although there may be an attempt at a late vote. Should the rule change remain in place, a by-election will be held among the PLP to fill the vacancy. Shabana Mahmood, shadow chief secretary under Harriet Harman, is widely believed to be the favourite for the position.