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Jeremy Corbyn, leader of the U.K. opposition Labour Party, poses for a photograph following a Bloomberg Television interview at the Confederation of British Industry annual conference in London, U.K., on Monday, Nov. 21, 2016. Corbyn said business leaders and trade unions have expressed concern that Britain is heading for a "hard Brexit" that would be "very very damaging" for the U.K. Photographer: Jason Alden/Bloomberg Image Credit: Bloomberg

Last week I was in Sleaford, Lincolnshire: a market town, population 17,000, with a very middle-English mixture of Barratt houses and boarded-up shops, and a political atmosphere defined by the increasingly fraught aftermath of the EU referendum.

Thanks to the resignation of its former Tory MP, Stephen Phillips , a leave supporter who admirably quit over the government’s high-handed attitude to parliament, there will be a byelection in the constituency of Sleaford and North Hykeham on 8 December, which the Tories will easily win. However, since 62% of people in this part of the country voted to leave the EU, the visit offered an opportunity to find out where Brexit Britain is now at.

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Vox-popping for the Guardian’s Anywhere But Westminster series on the main street, within minutes a deep generational divide was clear. Among the over-60s, immigration was a ubiquitous topic. “Brexit means Brexit” was a refrain. And, for reasons that seemed to have more to do with symbolism than practicalities, people wanted the UK out of the EU right now.

The young people I met, by contrast, were relaxed about immigration, and blithely uninterested in the matters of British – or rather English – identity and “control” that so exercised older people. Not entirely surprisingly, the under-30s here who had voted chose the remain option, and were now more worried than ever about the future: an anxiety which informed a few guilty expressions from the Leave voters higher up the age range. “My granddaughter says I’ve buggered up her future,” one woman told me.

Out in the country, this is the reality: loud voices wanting hard and fast Brexit but also plenty of people unsure about what exactly it will mean, and often convinced that leaving the EU will have dire consequences for lives that are already insecure and uncertain. In any decently functioning democracy, the latter group would surely see its views reflected in mainstream politics. The government might couch its approach to Brexit in terms of pragmatism; the opposition would give strong voice to people’s anxieties. But no. Given the pernicious idea that the vote to leave was “overwhelming”, Brexit means Brexit. And that, apparently, is that.

Which brings us to the Labour party, and its approach to the issue that now defines British politics. When it comes to our relationship with the EU, what does it want? Will it hold the government to account? And does it have anything to say to the millions of people – including all those younger voters – so worried about where we are headed?

Last week the shadow chancellor, John McDonnell, made a speech at a “tech hub” in central London. He correctly portrayed whole swaths of the country as places defined by “dead town centres, job deserts, stagnant wages, and the constant feeling that the basic things we rely on – our jobs, our savings, our homes – are not safe”. But then he moved on to the question of how Britain should leave the EU, and all sense was lost.

“It is time we all were more positive about Brexit,” he said, claiming that leaving the EU opened up “enormous opportunities”. He also rejected trying to block or delay article 50 in parliament – even, it seemed, as a means of ensuring that our split from the EU avoids the kind of recklessness advocated by some Tories – because to do so would be “against the majority will of the British people and on the side of certain corporate elites”.

Labour’s Brexit spokesman, Keir Starmer, was said to be “ furious ”. But, as often happens these days, it fell to the Green party’s Caroline Lucas to sound a note of loud alarm. “Labour’s premature capitulation on article 50 leaves those of us who oppose a hard Brexit in a weaker position,” she said. Quite so.

In keeping with the image of people who affect to be concerned about Brexit while being fundamentally comfortable with it, Labour’s supposed red lines on Brexit are comically weak. Seemingly thanks to the arcana of EU state aid rules , Labour, rather than insist that the UK should remain a member of the single market, is insisting on mere “access” to it, and the protection of employment rights currently enshrined in EU law. But “access” is pretty much meaningless, and the issue of employment rights has been answered by Theresa May herself.

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Besides, these are not red lines at all: if the party dare not hold to them with the threat of blocking or delaying article 50, they amount to nothing. Meanwhile, as the gaping hole in Labour politics leaves room for the rumoured comeback of that ghoulish irrelevance Tony Blair , one gets the sense from the Labour leadership that Brexit – and hard Brexit at that – is exactly what they want. Strange that these people stand at the head of a movement said to be powered by the young.

Among Labour MPs, the mood is as restive and perplexed as ever. The letter this week in the Guardian, signed by 90 MPs and MEPs and warning against hard Brexit, was a thinly coded restatement that they would like their party to back the UK remaining in the single market. Many of them would also like to move towards something the indecipherable Corbyn/McDonnell position leaves untouched: some measure of control over free movement. The EU would presumably scoff at such audacity. In any event, it is hardly likely that Labour will be involved in any negotiations. But the basic point is simple: an insistence on single market membership is a coherent and clear position, by far the best option for the economy, and a vivid point of difference with the government.

But this is about a lot more than the Westminster game. It is also about a view of the future, the left’s chances of speaking to an anxious generation who will sooner or later sit at the heart of our politics, and the idea that in times as grim as these it might fall to the supposedly progressive side of politics to sketch how the worst effects of our split from Europe might be avoided. That, surely, is the least we should expect.• You can comment on this article and others on our Your Opinions thread, which opens every Wednesday at 10am

— Guardian News & Media Ltd

John Harris is a journalist and author, who writes on a range of subjects built around politics, popular culture and music.