Labour Kremlinologists will be intrigued to hear Momentum chief Jon Lansman talk up McDonnell and talk down Corbyn on BBC PM. Lansman, an old Bennite who has known both men for decades, says McDonnell is the one who’s been “leading” on making Labour electable, and that Corbyn doesn’t represent their core voters:

JL: “We alienated our core voters, millions of them, they’ve gone to UKIP and to the SNP, because they don’t see Labour as representing them anymore.”

BBC: “You think Jeremy Corbyn does?”

JL: “Jeremy Corbyn could. I don’t think he does. I think he could.”

BBC: “What does he need to do?”

JL: “What Jeremy’s got to do now is, he’s kind of got to come up with a positive programme, not opposition to what the Tories are doing. It’s actually John McDonnell who is leading on that stuff.”

Momentum have previously said McDonnell would be their candidate if Jezza fell under a bus, praising the Shadow Chancellor’s “pragmatism”. This is one to watch after the referendum if and when the challenge to Corbyn comes…