Elections 17 May 2018 Jeremy Corbyn's most powerful allies are at odds in the Lewisham East by-election Photo: Getty Sign UpGet the New Statesman\'s Morning Call email. Sign-up Who’ll be Labour’s candidate in Lewisham East? The battle has taken an interesting broader dimension as far as Labour’s new faultlines go, as Momentum have backed one candidate (local councilor Sakina Sheikh) while Unite have backed Claudia Webbe, an Islington councilor and a member of Labour’s ruling national executive committee (who was elected and is once again a candidate for the Momentum-backed slate on the NEC). It means that the parliamentary selection pits two of Labour’s most influential power-brokers against one another (the GMB, another major player, has yet to endorse a candidate, while Unison have endorsed Janet Daby, another local councillor). Although it is not the first time Momentum and Unite have backed different candidates in parliamentary selections, that Lewisham East is considered a sure thing for Labour increases the value of the prize on offer. However, I wouldn’t get particularly too excited about the division. Momentum and Unite have picked different candidates before, as have Momentum and their two affiliated unions, the TSSA and the CWU. Unlike the split over who should be Labour’s next general secretary, there aren’t even any particular institutional or political faultlines at work: it’s just about who is considered best-placed to win. Nor would I draw any particular inferences about which side is the more effective based on who wins this one. The very short selection timetable means that the usual advantage of union backing- more money – is less useful than it otherwise would be. That Webbe is not a local further increases the challenge of overcoming local opposition in such a short time. And for Webbe, the stakes are particularly high: members of the Momentum slate sign a self-denying ordnance not to seek parliamentary selection as MPs are not allowed to represent lay activists on the NEC. If they become MPs during their term of office, they are automatically booted off the NEC, with the beneficiary the nearest runner-up in the last NEC election. (Should Webbe become the MP for Lewisham East, she will be replaced by Bex Bailey, a Corbynsceptic.) That demand meant that Rhea Wolfson and Christine Shawcroft both opted not to re-stand for the NEC in order to seek parliamentary selection. But the requirement not to stand only applies for the two years that the NEC is sitting which is why Webbe is allowed to run for this one: but if she fails, she will face a long wait for a second attempt. › Don’t be fooled by Deliveroo’s share handout – 30,000 workers are excluded from its success Stephen Bush is political editor of the New Statesman. His daily briefing, Morning Call, provides a quick and essential guide to domestic and global politics. Subscribe For more great writing from our award-winning journalists subscribe for just £1 per month!