In the United Kingdom, most protest marches have two things in common: they finish up outside the Palace of Westminster and they end in failure. More than a million people marched against the Iraq War – then Britain joined the US-led invasion of that country anyway. More than 400,000 marched against the ban on hunting foxes with hounds – and the measure passed through parliament regardless. And despite 100,000 people marching in support of a referendum on the final Brexit deal, that won’t happen either.

The Conservatives oppose a so-called People’s Vote for two main reasons. Some believe that if there is the possibility of Britain revisiting its decision to leave the EU, the 27 remaining countries in the bloc have an incentive to offer a bad deal. One minister, who backed Remain in 2016, despairs of the predominance of newspapers such as the Financial Times and the Guardian in the corridors of power and urges her opposite numbers to read the Daily Mail and the Sun to get a feel for the forces arrayed against pro-Europeans in Britain.

Added to them are Brexiteers who fear they would lose a rerun of June 2016’s vote. For a wing of the Conservative Party, securing Brexit now outweighs all other concerns. It is more important than seeing off Jeremy Corbyn at the next election, more important than the health of the public finances – and more important than the British economic model. The philosophy of this faction could be summed up in a phrase: “fuck business”. That is the reply that Boris Johnson is reported to have given to a European diplomat’s query about what a hard exit would do to British businesses. Yet the Foreign Secretary’s colourful language is simply a more forceful version of the sentiments heard from Theresa May, Jeremy Hunt and other ministers in response to the growing unease among British industry.

Most Brexiteers don’t fear a referendum rerun, however. They believe that putting the question to the public a second time would secure a more emphatic version of the original answer. They gleefully talk up the possibility of a second referendum, claiming that re-entry to the EU would mean accepting British membership of the euro and the loss of our previous privileges and opt-outs. Abandoning Brexit would be depicted as a national surrender.

That narrative would be an easy one to sell. I recently attended focus groups in Slough, a Labour/Tory marginal seat that voted narrowly for Leave. Even among Remain voters, the fear that staying in the EU would mean “giving up the pound” was mentioned unprompted by participants.

That fear is a major reason Labour MPs are reluctant to back the People’s Vote campaign. One MP put it bluntly: “I don’t want a second referendum for the same reason I didn’t want a first one: we aren’t in a position to win it right now.” Even some of the MPs who have publicly called for a People’s Vote don’t really want one, at least not yet. This group of MPs want to keep alive the idea that British voters can think again about their relationship with the European Union, even though they believe that they would lose any referendum vote held in the short term. (Thanks to the opposition of the Labour and Tory leadership to a second vote, supporting the idea is risk-free.)

Not all antipathy to the People’s Vote is driven by fear of what its outcome would be. Some Labour MPs simply fear losing their seats if they are seen to go against their voters’ wishes, particularly on the free movement of people. These MPs would vote against staying in the single market even if the Labour leadership changed its position and they were therefore forced to rebel.

The existence of this bloc means that, for the government to be defeated on the final deal, more than 30 Tory MPs would have to break ranks and vote against their leadership. This seems… ambitious.

Given the obstinacy of this Labour grouping (which includes English MPs from the north and Midlands such as Caroline Flint, Gloria De Piero and Gareth Snell), it seems strange that the organised Remain campaigns are wasting their energy on trying to make Jeremy Corbyn change his position. A youth grass-roots campaign called Our Future, Our Choice recently paid for billboards depicting John McDonnell and Nia Griffith in the pockets of Brexit ultras Jacob Rees-Mogg and Nigel Farage to be transported through their constituencies. The same campaign used a smiling photo opportunity with Justine Greening, the Conservative MP for Putney, who ultimately ended up voting for the government’s hard Brexit line.

This seems odd. Although Corbyn is undoubtedly a Eurosceptic, if the balance of forces in the Commons or the path to Downing Street would be eased by softening his stance, he would do it without thinking twice. His current position makes sense because voter resistance to the free movement of people is what is driving the United Kingdom towards the hardest of exits. The ability to work, travel and live where you please within the bloc is the most popular part of membership among the other 27 members of the club, so there is no appetite to abolish it. But while so many British voters – and, by extension, Labour MPs – are unwilling to countenance free movement, the only politically viable Brexit will be a hard one and the only outcome of rerunning the referendum will be defeat.

The difficulty is that no one really knows how to sell British voters on free movement. However, they can at least imagine what it might take to convince Corbyn to change Labour Party policy on the single market. That’s the real reason Remainers spend so much time on Corbyn: because the alternative is to admit that the referendum has been lost and that the path back to membership of the EU is a long and fraught one.