Jeremy Corbyn may not have one drop of Scottish blood but his campaign was laden with learning from Scotland’s referendum. So, what are the lessons from Yes 2014 and Jez We Can for the EU referendum? Failure to learn them might, just might, result in Brexit next year. We may not be able to count on Nigel Farage being an Alex Salmond – a useful, vote-losing villain – to help win this referendum. So here are five reflections on the things we know we now know.

First, we are living through a period of post-truth politics. As I spoke at 100 impromptu public street meetings last year, standing on top of my Irn-Bru crates, I felt its surge in Scotland’s towns and cities. A belief system grew that cheerfully shot the messenger and relegated opponents’ truths to malignly motivated opinion. We heard a quiet echo of that attitude during the Labour leadership contest.

And it will be back again for the EU vote, this time with a patriotic, outsider’s vengeance. The collapsing global price of oil should have, and still can, burst the pro-independence bubble. Similarly, it didn’t seem to matter that Corbynomics wasn’t fully costed, or that he had met all sides in the Israel/Palestine conflict except the Israelis. His supporters saw him as a cause, not a candidate. For the EU referendum, we have to come to terms with a politics in which wishful thinking can morph into a popular orthodoxy. The era of impeccably researched documents winning the day on their own is gone and gone for good.

Second, don’t pander to populism, because, unchallenged, it has an appetite that can never be satisfied. The Scottish Labour Party’s demise began with losing an argument it didn’t make a quarter-century ago. As partisan support for Labour diminished, we continued to borrow votes from the Scots while losing their affection. For some in Labour’s ranks, that didn’t seem to matter. Although I wasn’t a leading advocate of that approach, it would be churlish for me not to accept my share of culpability. We should have made a case against the nationalist shibboleths about oil, the Barnett formula and defence much earlier, and then more often. Instead, we implied: “Aye, we know that’s what you think but if you vote SNP you’ll get the Tories.”

It’s not too late for Scottish Labour to recover but it’s well past midnight in the efforts to overcome the current populist outburst in British Labour. Yet that’s what comes from splitting the difference with people, whether nationalist or hard-left, whom you know to be well intentioned but irreconcilably wrong. All of which meant that when ABC (Anyone But Corbyn) spoke, it felt that many good people just didn’t want to know. The lesson is: treat the public as informed adults, know what you believe in, and tell your truth. Incredibly, so close to the EU referendum, some quarter-baked opinions still travel as quasi-facts. “We are run by a remote capital from beyond our own country.” “We would prosper outside of the multination single market.” “We can have a bigger say in the world separate from the Union.”

It’s the SNP’s 2014 playlist all over again. In many ways, the “Britain Out” campaign will sound a lot like an SNP tribute band.

Third, vote to remain but not to stay the same. Having powerful media allies and wealthy campaign backers is seductive but can also be harmful. In a politics where parts of England are tempted by eccentrics and Scotland by populists, it is deadly to be seen as an establishment fix. Instead, we need a vision of big change that is primarily pro-Britain, not pro-EU. Of course, this will necessitate a distinctive Labour argument. That doesn’t in itself preclude a cross-party effort. The winning campaign to stay in the UK was unfairly caricatured as a dull defence of the status quo. By contrast, Scottish independence and Jeremy Corbyn were seen as being free from politics as ­normal. All the more remarkable from an eight-year-old SNP government and from Jeremy, first elected to parliament in the week of Liz Kendall’s twelfth birthday.

Fourth, we have to convince early and convince often. I met very few people during Scotland’s referendum campaign who switched sides in the final hours. I sometimes felt that it would have been more productive debating the Immaculate Conception with my priest than fiscal autonomy with a Nationalist. I know that the Labour leadership candidates were sometimes confronted by, “I’m voting JC. I don’t care what you say.” A lesson for the EU campaign proper is that once they’re gone, they’re not coming back.

Fifth, social media has at last started to deliver on the decade-old hype that it will help change politics. In a post-deference culture, many outsiders viscerally feel that the BBC has been captured by an establishment elite. This isn’t a boring rehash of the “social media matters” shtick; it is a statement that, in these emotion-fuelled insurgencies, peer-to-peer social media is increasingly the broadcaster of choice. It was huge in Scotland. In this year’s general election, Scottish Labour spoke to more people than the SNP did. I know I’ll be kicked for this, but if I had my time again I would spend almost every penny we put into those face-to-face conversations on Facebook.

And one final thought. It will get personal. All campaigns attract an angry minority. But the other side’s minority will be bigger and fantastically noisier. The online treatment of the gutsy Liz Kendall as well as the bizarre anti-Semitism were vile. In Scotland, post-referendum passions are calming but remain strong. The greetings from strangers in the street sometimes still suggest that I’ve changed my first name to “Murphy” and my surname to “YaBastard!”.

That’s a different debate. And I’m going to put it down as just another example of post-truth politics.