Jeremy Corbyn has just made his biggest mistake yet

“If you don’t read this piece, you’re a Tory.” Not a terribly persuasive argument is it? Hardly designed to pique your interest or entice anyone in but the most committed bearers of the Red Flag. If you want to communicate with people, shaming them simply doesn’t work.

The most recent polling tells us that the Conservatives are leading Labour by 39 to 26. Half as many people again would choose, at this particular point in time, to vote Conservative rather than Labour at this moment in time.

Polls and governments change, and when they do so it is because voters can be persuaded to change their minds. The job for Jeremy Corbyn is to persuade people to make that shift between now and the next election. But if he wants to achieve that, he will need to think again about how the tactic of persuasion works and how best to reach out to the as-yet-not-persuaded.

Labour has promised a rebooted “populist Corbyn” for 2017. I hope this means fewer unforced errors like this weekend’s Twitter exchange with the Economist’s Britain editor, Tom Wainwright.

I understand the siege mentality that Corbyn’s office must be under. It’s a tough job at the best of times and, frankly, it’s not paranoia – there are an awful lot of people are out to get him. Not ideal circumstances in which to try to convince the rest of the country to support you.

But politics isn’t easy. Politicians must have a skin thick enough to come through the hostility thrown at them to reach the voters regardless. Equally, they must approach every single one of those voters as persuadable. They must understand that their approach must be about being open to the majority of the voters, not a closed off clique of puritans.

This is not the same as asking the leadership to triangulate on policy. No return to third way politics will work for Jeremy, the Labour Party or a vastly changed country. Authenticity is Corbyn’s stock in trade. He falters when asked to present ideas he doesn’t believe in, but is best able to communicate when passionate about a cause.

To win an election, Corbyn and his team must treat voters with respect and spend time actively trying to change their minds, not writing them off as beyond hope. One thing populists do is to present their position as “common sense” – and you can’t do that if you frame all your arguments around who you are not and what you stand against. A populist Jeremy Corbyn would be presenting his values as our shared, common values; finding the common ground that unites us all, not using every possible excuse to make the Labour tent smaller and purer.

Doing politics differently is fine, but the ultimate goal has not changed: if you want to enact socialist policies, you have to actively persuade people to vote for them. You won’t achieve this if you tell everything who thinks differently that they are simply wrong. A good first step would be to stop labelling everyone who disagrees as a Conservative.