As the Brexit negotiations play out, Jeremy Corbyn’s longstanding Euroscepticism is becoming more prominent. While the Labour leader never hid his distaste for the free market forces associated with the EU, his party’s stance on Brexit was rather more ambivalent – something that helped rather than hindered it in the general election.

But now we pretty much know how he feels about the single market, free movement and which parts of our EU membership he wants to protect as we leave. Workers’ rights, the rights of EU citizens to stay – with family reunion guaranteed, protecting Parliament’s role in scrutinising the legislation, incorporating the European Charter of Fundamental Rights into UK law, and more stipulations that make up a “jobs-first Brexit”.

As this has been unfolding, I’ve heard from numerous sources who expect this to be Corbyn’s Achilles’ heel among his mainly pro-single market base. A source close to a cabinet minister predicts that young Labour voters – the majority of whom were Remain voters – will realise that their leader isn’t sticking up for what they believe in, and split the left vote by going Lib Dem at the next election. This is a common argument among Lib Dems too.

But it’s hard to believe when you look at what has happened so far. Corbyn’s participation in the Remain campaign was disappointing to some party members, supporters and Momentum figures I spoke to afterwards, but most stuck with him – realising from his voting record that he’s never been much of an EU fan.

Yes, it put a few people off – a handful left the party – but most supporters find him appealing because he’s a man of principle. Left-wing ideological opposition to the EU is one of those principles, and he’s sticking to it.

Also, look what happened when he was opposed by someone standing on a pro-European platform. The Labour MP Owen Smith called for a second referendum, making it central to his campaign against Corbyn in the second Labour leadership election in 2016. He lost abysmally.

What we learned from the Tory campaign is that voters do not only care about Brexit. While Theresa May made the debate all about who would be negotiating Britain’s departure, Labour was talking about taxation, education, and the NHS. Labour voters prioritise a progressive outlook on such subjects to the extent that even the most pro-Remain among them are able to give Corbyn their support. Even some Labour-leaning EU citizens in the UK I’ve spoken to are willing to carry on backing him – despite his opposition to free movement.

“I kind of shrugged off those comments and they didn’t bother me massively,” Teresa Ellhotka, a 24-year-old PR who moved here from Austria in 2016, told me. “My mind about Jeremy Corbyn hasn’t changed drastically as his ideas and visions are, in my opinion, still very progressive.”

Basically, if Corbyn’s track record on Brexit so far hasn’t put off his supporters, it won’t now – especially not with a whole manifesto of more attractive policies under his belt. Of course, these could be difficult to carry out after a hard Brexit hits our economy, but it will be the Tories – not Corbyn – who get the blame for that. As my colleague Stephen writes, “neither Tony Blair nor David Cameron were blamed for the failures of policies they had supported in Opposition”.

And what are the alternatives? A hard Brexit-chasing Conservative party with no offer to young or millennial people? Or the weak Liberal Democrats with a leader who is associated with the Tory-led coalition? Yes, they’re pro-European, but the election result showed that isn’t a sure-fire way to Remain voters’ hearts. As for within the Labour party itself, the infighting of the past couple of years – and Corbyn’s strong electoral performance – have taught us that anyone rivalling him would be crushed.

Corbyn is in the enviable position of taking one side in the Brexit debate, while keeping all his supporters on side. Other politicians who have failed to do this are wrong to predict his downfall.