A confession: I didn’t originally want a ‘left’ candidate in the Labour leadership election. My view was that, in the midst of general post-election demoralisation, a left candidate could end up being crushed. Such a result would be used by both the Labour party establishment and the British right generally to perform the last rites of the left, dismiss us as irrelevant, and tell us to shut up forever. I originally toyed with starting a campaign to enlist Lisa Nandy, the straight-talking ‘soft left’ Wigan MP, but she had just given birth, so that wasn’t going to happen. [https://twitter.com/OwenJones84/status/600625839231893505] The Shadow Cabinet minister Jon Trickett was originally approached by several people asking him to stand: for the reasons above, I suggested it was bad idea. Instead we began brainstorming a ‘Not The Labour Leadership’ tour alongside a presumably dispiriting leadership contest with three candidates dancing on the head of a pin, with the aim of helping to rebuild a grassroots movement.

In all honesty, when Jeremy got the nominations, my instinctive reaction was somewhere between nervousness and trepidation. On top of the reasons above, I was worried (as someone who first met him a decade ago) that the personal characteristics that, in actual fact, have contributed to his popularity amidst a general anti-Westminster mood — understated, modest, his anti-firebrand disposition — might count against him. (On that count, I was clearly very wrong). Obviously there was no question I would do anything other than wholly support the campaign — I’d be a charlatan to do anything else. As one of the only people with a media platform who isn’t hostile to Jeremy — let alone supportive! — I’m pretty much duty-bound to be helpful and rebut the stuff thrown at the campaign as best I can.

But I originally felt that if he came third, that would in itself be a huge political achievement. The big contribution of Jeremy’s campaign, I felt, would be to put policies on the agenda, shift the terms of debate, and help rebuild a grassroots left movement; that this achievement could be built on, and crucially used to shift public opinion.

If you’d asked me privately back in May what I thought about a left candidate winning the Labour leadership, I’d have responded simply: “I don’t think we’re ready for that yet”. We’d need to spend the next few years building a formidable movement, I’d have argued, to win support for the policies we believe in, and to shift attitudes on a number of issues. Such a candidate would face formidable opposition from both within the Labour party, and from very powerful groups outside it, too. Without a big grassroots movement behind it, such a leadership would be crushed like an insect in someone’s hands.

But obviously the thing about history is that it doesn’t unfold in ways you can control. “Hey, history, tell you what, could we run this three years instead when we’re more ready?” A grassroots movement and political phenomenon has emerged now. It could well be that, without Jeremy’s candidature, it would never have emerged. It has to be engaged with as constructively as possible. It is like riding a tiger — a tiger that, yes, may well throw you off.

Anyone who predicted this huge grassroots movement would emerge in such a short space of time is bluffing. The packed meetings across the country, with 1 in 40 inhabitants of Llandudno coming to hear Jeremy speak; hundreds of thousands registering as members or supporters of the Labour Party (has there even been such an increase in the membership of a party across Britain in such a short space of time?); YouGov polls suggesting overwhelming support for Corbyn across the Labour party; polling suggesting that not only he is now the preferred candidate of Labour supporters, but does best among supporters of parties ranging from UKIP to the SNP; and that as well as poll suggesting cross-generational support, some of his most enthusiastic supporters are young people whose futures are threatened, and have few politicians championing their interests. This movement — and building it after 12th September — matters, because a Corbyn leadership would sink without it, and quickly too.

For some opponents of Corbyn, support for his campaign is an outrageous self-indulgence, the promotion of unelectability and thus the betrayal of the people Labour was founded to represent and who need it most. Firstly, if a candidate can not enthuse enough people in a semi-open primary of Labour supporters, and they lose this contest, they are by definition unelectable. And secondly, it is beyond me how Labour voters who plumped for the SNP, or people who voted Green, or UKIP, or who didn’t vote at all, are realistically going to go, “Oh, now that Andy Burnham/Yvette Cooper/Liz Kendall are leader of the Labour Party, I’m definitely going to vote for them.” The polling suggests that — although the general public doesn’t know the candidates, and with the exception of Kendall, Jeremy least of all — that if anything he has the edge amongst them.

The Tories are said to be privately delighted, despite the pronouncement of some Tory supporters who believe that Jeremy should not be underestimated. They believe his election will be a catastrophe for the Labour party. In the case of these people — drunk on triumphalism — this is deeply sincere. There is no doubt that the odds against a party led by Jeremy are formidable — yes, they can be overcome, but we have to be aware of what they are if we are to achieve this.

The current internal schism within the Labour Party is partly the product of our electoral system. In other democracies, there are often two left parties — one ‘centre-left’, the other more radical. They compete against each other but frequently form governing coalitions together. In Britain, they are in the same party. ‘First-past-the-post’ is increasingly untenable as a system because of the political fragmentation resulting from fragmentation in wider society — because of changes like deindustrialisation, a more transient workforce, immigration, people moving more, an ageing population, and so on. Having broad ‘left’ and ‘right’ coalitions fighting elections under the same banner seems to make less and less sense, but the electoral system compels it to be so.

The Corbyn surge is part of a general trend of political discontent bubbling across the Western world, manifesting itself in progressive ways but also reactionary ways, too: Podemos, Syriza, Bernie Sanders, the SNP, UKIP, the National Front, the True Finns, and so on. My fear is that, without this progressive Corbyn surge, that discontent could end up being funnelled to UKIP.

A strong movement is a precondition for success. But it is no guarantee of it, by any stretch. If Corbyn wins, the challenges, as I say, will be enormous, but not insurmountable. I’m not writing this to dampen people’s hopes, or to prepare excuses, but because people have to be ready and prepared. See those guns in the distance? Yeah, well we’re running towards them. We have to be hopeful and optimistic, but also prepared for what awaits. So here’s my thoughts about the problems, and what can be done about some of it.