I joined the Labour Party to stop Jeremy Corbyn

The Labour party cannot be a party of protest, and yet you get the sense that Corbyn would rather be in the right, and on the right-hand side of the House of Commons

Corbyn may have won the youth vote, but how did he support them during the referendum? (PA)

Corbyn's shadow cabinet has collapsed with the statesmanship of cockroaches scuttling from a bathroom light. The infighting, the backroom deals – it's just politics as usual, right?

Yet there is something different this time. Ask his supporters and you’ll hear that this coup is against Labour's members as much as its leader. They voted the Islington MP in by a landslide not seen since Blair cruised it in 1994. That mandate stands, the people have spoken, Corbyn has to stay.

But the voice of party members is not the voice of its support. Of the 9.3m people who put a cross in the box of the Labour leader, 2.5m say they probably won't do it again.

And can you blame them? The biggest success of Corbyn's "new politics" is stasis. He's won four by-elections, yes. But in seats Labour already held. May's local election results were trumpeted as being not abysmal. "Clearing a low bar," isn't the kind of promise that fires up the disenfranchised.

Which is why I've joined the Labour Party, to support those who want Corbyn gone if he manipulates his way into the pending leadership election. To counter the tide of Momentum, as they bolster a leader who couldn't get on the ticket with nominations and will only be able to stand if his lawyers find an incumbency loophole.

Look at Momentum's members, at Corbyn's most vociferous supporters, and you see youth. It seemed like Labour might have finally found a man to energise that electoral unicorn – the non-voter. They didn't have to compromise their values, to shift right to steal Tory voters. Corbyn would deliver that left-leaning chunk of under-30s who'd never engaged with politics.

But how can any of them can vote for Corbyn's Labour party when he failed to deliver their referendum result? When he was so impotent on the campaign trail and, say the whisperers, actively sabotaged his party's message. Yes, the majority of Labour voters voted to remain. But a third ignored his message entirely, voting against their own self-interest because he couldn't hide his contempt for the EU. That mandate crumbles under the weight of his ineffectiveness.

Corbyn's liberal credentials are in no doubt. His ability to lead, to deliver power, is. The Labour party cannot be a party of protest, and yet you get the sense that Corbyn would rather be in the right, and on the right-hand side of the House of Commons, than compromise to cross the aisle. He's lost support from the electorate and from his own MPs. He cannot form a meaningful shadow cabinet. The unions and a cabal of grassroots campaigners prop him up, but he's holding the Labour Party hostage. Under Corbyn, the Tories get a free pass. Idealism is for nothing if you can't win seats.