UK 8 January 2020 Unison's backing is a triple boost for Keir Starmer The support of the UK's largest trade union, which is generally regarded as Labour's swing voter, is a coup – but it's not all upside. Getty Images Keir Starmer delivers a speech at the Labour conference in 2019. Sign UpGet the New Statesman's Morning Call email. Sign-up Unison, the United Kingdom’s largest trades union, has backed Keir Starmer for the Labour leadership. The endorsement of Unison, generally regarded as Labour’s “swing voter”, is a triple coup for Starmer. Firstly, it will fuel the narrative that the contest is his to lose – which is pretty meaningless but is, of course, nice to have if you are the candidate people are saying it about. The second, and more important boost, is that it puts him closer to qualifying for the contest itself. To make the ballot paper, candidates need secure the support of ten per cent (22) of Labour MPs and MEPs, a hurdle Starmer has already cleared, and then also do two of the following things: to either secure the support of five per cent of constituency parties or of at least three affiliates, two of which must be trades unions, and comprising at least five per cent of the total affiliate pool. Unison are so large that they meet the five per cent threshold in their own right, which means the support of any other union combined with another organisation, be it a third trades union or a socialist society, will put him on the ballot. He is as close to certain as you can be of meeting those hurdles, and with it a place on the ballot. That links to the third boost this gives Starmer: it makes it harder for his rivals to reach the ballot, too. While Rebecca Long-Bailey and Jess Phillips are certain to secure the nominations among the parliamentary party that they need, only Long-Bailey is guaranteed to be able to pick up enough support from trades unions to join Starmer in the final, one-member-one-vote stage of the contest. Phillips – and Nandy, whose strong performance at the PLP’s closed-door hustings means she is highly likely to get the support of enough MPs to reach the ballot – however, have a trickier route to the final ballot. Phillips is not going to get on via the affiliates route and Nandy’s theoretical route there ran through Unison or the GMB. If the GMB decides that its interests are better served by lumping behind the frontrunner then there is no plausible path to the ballot for Nandy via the affiliates route. That means that both of them will need to get on via the Constituency Labour Parties. Labour have never used this process to nominate candidates before, so how CLPs decide to play it is unknown. They might decide to endorse their preferred choice – which advantages Starmer and Long-Bailey – or they might decide to prioritise as full a range of candidates as possible – which advantages Nandy and Phillips. But taken together, Unison’s endorsement makes it much more likely that the Labour leadership will be a two-horse race between Starmer and Long-Bailey. Is that a boost for Starmer? It may give him the benefit of avoiding some of his more dynamic rivals. But casting the contest as a left-right battle may well be exactly what Long-Bailey needs to win this campaign – and a two-horse race may facilitate just that. › It'll take more than money for Boris Johnson to make good on his promise of better schools 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 daily analysis & more political coverage from Westminster and beyond subscribe for just £1 per month!