The one time I interviewed Wes Streeting at length, the striking thing was how firm this formerly ardent Remainer was in his view that Britain’s departure from the EU was a one-way street.

Actually, that’s not true – the most striking thing was an anecdote about his grandfather’s friend’s party trick involving five half-pint glasses and his, ahem, appendage. I’ll spare you the details, but it’s in his book, One Boy, Two Bills and a Fry Up. “I tell you what – the one thing that I didn’t think about when I put those words down on to the page was that I’d had to read them out loud myself on my audiobook,” he said when I asked about it.

But the headline when the interview ran in what was then The New European in July 2023 was “I can’t see a credible route back into the EU in the foreseeable future”, an eye-catching quote from what I still think was an absolutely fascinating interview.

Eye-catching because Streeting was a passionate Remainer who, following the referendum, kept it at the heart of his politics even when that was deeply uncomfortable for his own colleagues. In January 2018, when Jeremy Corbyn’s party was still pursuing something called, absurdly, a ‘Jobs-First Brexit’ (remember that?), Streeting was giving a speech to the Fabian Society’s annual conference in which he lamented how “we find ourselves in the terrible position where it is the Labour Party that currently stands as the single biggest barrier to the UK’s membership of the single market and customs union”.

Yet here we were, five years later in his Portcullis House office, with him saying equally uncomfortable words to the readers of the country’s most fervently pro-EU publication.

“We have got to accept where we are today, and I cannot see a credible route back into the European Union any time in the foreseeable future,” he said. “People need to get real about what’s possible.

“In the unlikely event that this country wanted to go through years and years of the same argument again about whether to rejoin, I’m not sure the European Union would have us back. And even with things like the single market and the customs union, we can’t become the mirror image of the Leave campaign. The Leave campaign basically said that Brexit would be really simple and would make everything better. And Brexit has been far from simple, and it has not made things better.

“I think Remainers, or some Remainers, are now at the risk of making the same mistake, of pretending there is an easy answer where we could rejoin the European Union and everything would automatically become better. Or even the single market and customs union, where, you know, being a rule-taker without a seat at the table is not without risk.

“Of course I wish things had been different, but the moral of the story, folks, is voting counts and losing hurts.”

I revisit these words today not to criticise Streeting, nor embarrass him, but because he might well be our next prime minister and it’s interesting. And also because it shows that, rather than a flip-flopper, he’s a realist.

In 2023, he may have been right that there wasn’t a credible route back into the European Union any time in the foreseeable future. Polls on the issue teetered rather than showing a significant and persistent majority in favour of rejoining, as they do now. That nice Joe Biden was in the White House, Donald Trump was assumed finished, enveloped, as he was, in innumerable court cases, and the world order, while not exactly healthy, was not the steaming wreck it is today.

It’s fair to say that, like John Maynard Keynes, when the facts change, Streeting changes his mind. Last year he appeared to hint at backing a customs union with the EU, telling the Observer a “deeper trading relationship” with Europe would be a means of boosting the UK’s economic growth – something which saw him accused of “setting out his stall” for a leadership bid by a “government source”.

Under a Streeting premiership, it is highly likely the government would take on a far more pro-EU approach, seeking the closest possible relationship with the single market. Streeting is not unique in wanting that – Andy Burnham has said he hopes Britain will rejoin the EU in his lifetime and Ed Miliband would back closer ties (Angela Rayner would also likely pursue greater integration although, like Corbyn during the referendum itself, it may be a “seven out of 10” priority).

Would Streeting go as far and step outside the “red lines” of the Labour manifesto – single market, customs union, freedom of movement – once ensconced in Downing Street? Would he feel bound by it?

None of this can we know for sure, but we may find out more over the coming days and weeks. Streeting may be the prime minister who guides the UK back towards its geographic home of Europe. He might equally likely be the new James Purnell, the minister who quit Gordon Brown’s government, found nobody following him and was left feeling as embarrassed as Streeting’s grandfather’s friend upon waking up and finding out that the previous night he’d done that trick again.