Can we just call the whole damn thing off? Could Brexit be stopped so that Britain can get on with the rest of its life? Is there a possibility of doing a Breverse? This question has been nagging away, always in the background and sometimes in the foreground, ever since the narrow victory for Leave. One reason this is so is because it is such a massive issue. Another reason is because such a massive issue was decided by such a tight margin in the summer of 2016.

The argument that there should be another vote before Britain heads out of the door has been pressed aggressively by unreconciled Remainers, the most vocal of them being Tony Blair, Sir Nick Clegg and Andrew Adonis. A hope that Brexit might somehow be averted also flickers in the breasts of some Tory Remainers, including members of the cabinet. They are handcuffed to a withdrawal policy that they still think is madness, even if they can’t say so openly. David Lidington, a former Europe minister, was reshuffled into the hole left by Damian Green and is now the prime minister’s key man on the cabinet’s Brexit committees. I rather suspect Mr Lidington would be a very happy fellow if he came out of the shower one morning to find that the last 18 months have just been a bad dream. Other senior figures around the top table, including the chancellor and the home secretary, would be the opposite of distraught if Britain didn’t leave in the end.

Enter, stage right, Nigel Farage. Remember him? Loves a pint. Loves a ciggie. Loves attention. His recent personal headline drought may be part of the explanation for why he has suddenly ventilated the view: “Maybe, just maybe, I’m reaching the point of thinking we should have a second referendum.”

Play Video 0:44 Nigel Farage backs second referendum on Brexit – video

Since the former Ukip leader did more than any other person to drive the demand for the first vote, this intervention matters, at least a little bit. He has since done something of a reverse ferret, but not before Remainers had welcomed this unexpected ally. “I agree with Nigel,” quipped Sir Nick via Twitter. Chuka Umunna, speaking for the ardent Remainers of Labour, remarked: “For the first time in his life, he [Farage] makes a valid point.”

They don’t, of course, agree on the why. The former Ukip leader thinks a second vote would “kill it off for a generation”, the Remain cause being what he wants to bury. For Remainers, another referendum is the only respectable way to cancel the first one. They have a persuasive case that the public ought to be asked whether they approve of the terms of the withdrawal. The country didn’t know what those were going to be in June 2016 and a democracy is no longer a democracy if there isn’t an opportunity for the voters to change their minds.

But if a second referendum happens, it will not be because of the arguments of principle in favour of holding another vote. It will only occur if key players feel it is to their advantage to put the question back to the country or if they are forced by circumstances to do so.

First of all, parliament will have to legislate for it. Is that likely? Not at the moment. Mrs May has consistently refused a further referendum on the grounds that pledging one would undermine her negotiating position by incentivising the EU to offer Britain a rotten deal. The prime minister would be under more pressure to concede another vote were she getting serious heat from Labour about it. Labour’s official position is that it does not favour a second referendum, though some of the frontbench, including the deputy leader, Tom Watson, have occasionally emitted noises that sound like approval of the idea.

Facebook Twitter Pinterest Theresa May might call a new vote if parliament rejected a Brexit deal. Photograph: Leon Neal/AFP/Getty Images

Jeremy Corbyn never sounds like an enthusiast for another vote, which puts him at significant odds with the vast majority of Labour’s members. According to the latest instalment of Professor Tim Bale’s penetrating study of the party memberships, 78% of Labour’s members think there ought to be a further referendum. That could matter later – I will discuss why in a moment – but for now Mr Corbyn isn’t backing the idea. So long as neither the prime minister nor the leader of the opposition thinks they have an interest in asking the country for fresh instructions it isn’t going to happen.

What could change that? Public opinion. If the national mood were to shift decisively, this would alter the context in which the politicians make their calculations about the likely appeal of backing a second vote. Remainers take note: Remain supporters just becoming more passionately Remainy is not what matters. What is required to force a rethink among the political decision-makers is clear evidence of second thoughts among a substantial wedge of Leave voters.

There are some identifiable trends in public opinion. Since Mrs May triggered article 50, there has been a downward movement in the proportion of voters who think the government is making a good fist of the Brexit negotiations. This is not surprising when so many of the Leavers’ promises, including the fantasy about it being child’s play to negotiate and the fib that there would be a massive windfall for the NHS, have been proved false. Levels of public anxiety about where Britain will be left by withdrawal have been rising. The numbers thinking we will be worse off out of the EU have gone up a bit and the numbers thinking we will be better off are down a bit. There are now fewer voters who think Brexit will increase Britain’s influence in the world and more voters who think it will diminish our global clout. There has also been a gentle rise in the proportion of voters who say they favour another referendum, though they are still outnumbered by those who don’t want one.

On the Leave/Remain question itself, opinion is still finely balanced. The polling company YouGov runs a useful tracker on this question. The most recent result has 46% thinking Brexit was the wrong choice, against 42% who say it was the right one. That suggests there is some buyer’s remorse, but not yet enough of it to induce a shift in the positions of the decisive political players. Public opinion will have to shift more dramatically before any of the politicians in a position of influence will be willing to act.

There is another way that a second vote might happen. This is if the government smashes into some kind of brick wall during the Brexit endgame. We have now entered what is commonly agreed to be the tougher phase of the negotiations, the talks that cover the future trading relationship and the length and nature of a transition period. The deadline to sign a withdrawal agreement – this autumn – is hugely ambitious given how much has to be dealt with and the combustibility of many of the issues. It is during this phase that it will become more starkly apparent that the UK cannot expect to continue to enjoy all the advantages of EU membership if it is not prepared to go along with all the rules. It is during this phase that Mrs May will have to become a lot more precise about her desired end state, with all the risks that clarity will ignite the many divisions within her party.

Conventional wisdom says that an agreement will be put together, but there is some chance that we end up in the car crash of a no-deal Brexit. In that circumstance, the Labour leadership would face colossal pressure from both its MPs and its members to back a second referendum asking the public whether they really wanted to go through with this. A lot of Tories would be horrified by the thought of going off the cliff edge. Enough to make it highly conceivable that they would combine with the opposition to demand a referendum.

There is another scenario that is worth thinking about. This is that Mrs May does a deal and then finds that parliament is so unhappy with what she has come back with that it will not endorse her agreement. The main significance of the pre-Christmas revolt by Tory backbenchers was that the government is now obliged to put the withdrawal terms into legislation. This can be amended or rejected in the Commons, where the government relies on the DUP for its majority, and in the Lords, where Tory peers are heavily outnumbered by the rest.

In the event that a Brexit deal is blocked in parliament, there will be a constitutional crisis and it is anyone’s guess what would happen next. A not unreasonable conjecture is this: Mrs May would feel there was no other option but to go to the people by holding another referendum. Remainers could not quarrel with that because they have repeatedly argued that the eventual terms should be subject to the approval of the people.

As of today, I’d say it does not look that likely that there will be another referendum before Britain takes it formal leave of the EU. What we can begin to see is how and why either Jeremy Corbyn or Theresa May or both could end up in circumstances in which they are forced to embrace the idea.