In the days after Labour’s crushing election defeat, John McDonnell summoned several young activists to discuss what had gone wrong. But as the group completed their post- mortem examination, they alighted on an arguably far more pressing problem.

Rebecca Long Bailey, McDonnell’s protégée and known by him as “My Becky”, has long been touted as heir apparent to Jeremy Corbyn. Yet to many on the left, the shadow business secretary is an unknown — and neither popular nor dynamic enough to preserve the left’s control over the party.

Those present included figures from Momentum, the pro-Corbyn campaign group, and Novara Media, a radical left website whose journalists are some of Corbyn’s most forthright advocates. According to one person at the summit: “It wasn’t bitter. The