With even Jeremy Corbyn’s spokespeople briefing against his new line on Brexit, readers could be forgiven if they are confused about what it means. So let me spell it out. It means the decisive rejection of the attempted Parliamentary Labour Party revolt against Labour’s conference position.

In December a group of Labour MPs, including some frontbenchers, began to agitate against the party’s commitment to a second referendum. They were backed by Unite general secretary Len McCluskey, the Communist Party of Great Britain and writers for the US title Jacobin. Their arguments were as follows.

“The working class wants Brexit and we have to deliver it for them.” “We can’t win marginal seats in the Midlands and parts of Yorkshire if we offer a second referendum.” “My constituency can’t understand why we haven’t delivered Brexit yet and will see a second referendum as a betrayal.” And from grassroots members: “I want to remain but can’t face a cultural battle with the far right in my town, which is what will happen in a second referendum.”

All these are decent arguments – and they are spurring some MPs, even now, to defy Corbyn’s attempt to back the so-called Kyle-Wilson amendment, which would ensure a referendum on any deal passed. Let’s address them one by one.

The working class supports Brexit? This relies on defining “the working class” as white, low-skilled people who live in small English towns. Look at the electoral map of Labour’s heartlands: does red Manchester support Brexit? Do Liverpool, Bristol, Glasgow and Newcastle? They didn’t in 2016 and they don’t now.

Look at the MRP polling done by Hope Not Hate and Best for Britain: it shows that, even in those constituencies where Leave scored high, and where Labour stands a chance of winning the next general election, on average there’s been a six percentage point swing from Leave to Remain – with working class women, young Labour voters and Muslims the groups most likely to change their mind.

And look at the real working class of Britain. It contains 2.7m European citizens, many of who are the very factory workers and farm hands the labour movement was born to represent. Do we include them in the British working class? Scotland did in 2014 – when it gave them the vote – so why can’t we?

And at a strategic level, the “working class supports Brexit” argument is weak in ways that, had any of these Labour rebels read a decent social science book, would be clear.

The Marxist historian Edward Thompson once wrote that “class is defined by men as they live their own history, and in the end this is the only definition”. For Marxists, a class forms itself around a project: it is not created by capitalist hiring practices, nor is it defined simply by income, or levels of education.

Thompson showed that the British working class defined itself around the projects of democracy and workers rights. It has repeatedly done so: the working class of the 1889 dockers’ strike was a self-defined entity around the project of mass trade unionism, self-help and political representation.

In the 21st century, as I argued in PostCapitalism, the working class has become sublated – destroyed and reformed – into a more networked and individualistic demos of resistance. Nurses are working class; junior doctors – when they go on strike – are working class; the precarious inhabitants of inner-city estates, plagued by drugs and crime but determined to self-organise – they too are working class. Students, eight out of ten of whom have part-time jobs, are also part of the working class. So are technically self-employed Afghan migrants driving Uber cabs. And yes, so too are what’s left of the industrial workforce.

The question is, what is the project this class has formed itself around? The answer is: progressive modernity and a globalised world. Their kids go on holiday in Ayia Napa; their grandparents own bungalows in Marbella; their bridegrooms get wasted on easyJet flights to Tallinn. On a Saturday afternoon, they watch football teams recruited from across the globe.

If we look at the British working class, not as a sociological category constructed by the media, but as a living cultural formation constructed by ourselves, one thing is clear: it does not support Brexit. It is increasingly defined by its opposition to Brexit. And it knows what it is up against: an alliance of the Tory elite and embittered white nationalists, drawn from all classes, around a rival project of ethnopopulism.

Next let’s take the argument that Labour cannot win the 40-60 English marginals it needs in order to secure power, if it supports a second referendum.

First off, it’s a kick in the teeth for Scottish Labour. If we accept, tactically, the need to take a position that might ingratiate us in Walsall, but will destroy us in Glasgow, what does that say about Labour’s priorities as an all-UK party?

But even in its own terms it is wrong. The leaked polling analysis commissioned by the TSSA union, and widely circulated in Labour’s top circles, shows that, if Labour is seen to facilitate Brexit, it will lose 16 seats in London and five in Scotland, while picking up no extra seats in the English Midlands.

This ten-page document, which I understand has weighed heavily on the minds of Corbyn’s inner circle, shows that the only chance Labour has of winning the next election is if it clearly opposes Brexit while, at the same time, the Conservative vote either splits or is suppressed because of the softness of the deal May delivers.

Those briefing that support for a second referendum will lead to “catastrophic damage” in the Midlands and Yorkshire have no polling evidence whatsoever in their support. Nor do they need any. Because all conversations with Lexiteers eventually lead to the claim that the polls are being rigged by the Tories to “confuse” Labour into taking the wrong position. Theirs is a world in which the last befuddled pensioner vox popped on TV is more important than the evidence of political science.

Third comes the argument: “I can’t look my constituents in the face if I back a rerun of the Brexit referendum.” Yes, it will be tough. But if Labour can show it was the Conservatives who, given the task of delivering Brexit, failed – and that it tried at all times to get a softer version of Brexit through – that argument can be assuaged.

Finally, there is the problem of what a second referendum will do to social cohesion and levels of anger in the civil society of Britain’s small towns. That’s real. I can sympathise with anybody who has had to live in a town where the pubs have become ideological war zones between Momentum and Ukip, with almost no liberal centre in existence. And I can understand people saying “I can’t face doing it again”.

Me neither. But in that case, stop telling me about Cable Street in 1936, or Lewisham in 1977. The labour movement has a proud record of taking on and defeating the far right, both physically and ideologically. In left circles there is a theory that, if we avoid an American-style culture war, we can get a left government without tears. But that culture war has been raging in working class communities for years, and has intensified as support for no deal has solidified during the barrage of media xenophobia.

Watching how the American left fights it makes me yearn for a breed of politicians like the Democrats’ Alexandria Ocasio-Cortez, Rashida Tlaib and Ayanna Pressley. Their attitude to white racism is to not to appease it, but to tell a better story based on the future, not the past. To speak defiantly about their own values – but to offer all of America an economic deal: real jobs, growth, investment and prosperity.

That’s what we need here. After the referendum result I, like others, accepted the need to try to deliver Brexit. But if no available form of Brexit is acceptable to the right-wing fantasists who actually want it, it’s not the left’s job to deliver it for them. Once we’ve exhausted all parliamentary routes to resolving this, it has to be put back to the people. And when it is, either in a general election or a referendum, Labour must argue from the heart.

We have to campaign on the values our core supporters in the real, progressive, multi-ethnic working class believe in, not on the values of people who will never vote for us.