As the dust settles after the Prime Minister’s Brexit speech yesterday, it’s worth exploring one of the points I picked out in my summary in more detail: what does her pledge that Parliament will get to vote on the eventual deal really mean in practice?

Sterling rose on the news, which is an indication that the markets believe this to be a hobble on Brexit – or perhaps even a roadblock to it. They’re mistaken to think so (as they were to imagine a vote on Article 50 might keep us in the EU), for reasons we’ll come to, but it’s instructive to explore why the misunderstanding might have arisen in the first place.

For those Remainers who still hope to keep Britain in the EU, the last few months have seen an exercise in giving ground.

They hoped that a legal case demanding a vote on Article 50 would open the chance of rejecting Brexit – they will likely get the vote but are set to lose it, and have already lost a Commons vote on the principle.

They tried to develop the idea of a “soft Brexit” in which we would stay in the Single Market, subject to the ECJ and signed up to free movement. The Opposition fumbled the concept, amid their fears about their own vote, while the Government has analysed the options and found the idea utterly wanting.

They demanded detail of the Government’s priorities, but not it’s negotiating strategy – which they got, but in so doing hyped up the announcement so much that it granted May days of positive headlines.

At each stage, the chances of somehow defying last June’s vote have narrowed. So now they must fall back on their next hope – a Parliamentary vote on the eventual deal with the EU.

Some seem to imagine that such a vote would, if it rejected the deal, have the effect of keeping us in the EU. May’s willingness to bring her plan to Parliament for approval should suggest otherwise – in realty, the choice which will be on offer is between leaving on the terms of May’s deal and leaving without a deal, ie with a trade relationship on WTO terms.

In that circumstance, far from voting against the deal as they might imagine, surely even hardcore Continuity Remain MPs like Tim Farron would vote for May’s deal over an alternative about which they regularly raise all sorts of lurid fears. Perhaps Corbyn and his followers might vote against a free trade deal as being too free market, but if so then they would still be voting for Brexit.

So again the options for keeping us in the EU narrow further. Indeed, there’s only one last holdout on the horizon for the really desperate – trying to prove that Article 50 is reversible.

If, once triggered, Article 50 starts an unstoppable two-year countdown at the end of which you leave the EU, then a parliamentary vote on the deal will definitely be between Brexit with a deal and Brexit with no deal.

But if that clock could be stopped – effectively telling the EU that we had changed our minds and wanted to stay – might the situation be different?

Yes and no. In that circumstance, a vote rejecting May’a deal still wouldn’t automatically mean we stay in the EU. If Article 50 had been triggered the clock would still be ticking and, assuming the deal vote was shortly before the two year deadline, we’d still be steaming towards exit deal or not.

What would be different would be the minutely slim possibility that Parliament would then be able to cancel the whole Brexit exercise, if MPs were too frightened of the prospect of exit on WTO terms.

Thinking about the practical requirements of doing so shows how unlikely a prospect this is.

MPs and peers could vote to cancel Brexit in the same sense that they can vote against triggering Article 50 – it would be within their theoretical power but the weight of political reality presses against it. The Conservatives know defying 17.4 million voters would splinter their party and hammer them in the polls. Labour look at Scotland and shudder at the thought of giving UKIP the chance to replicate the SNP’s capture of red heartlands. Peers don’t fancy pitting their unelected chamber against the biggest vote for anything in British democratic history.

Plus, this route involves a huge gamble. Any MP hoping to prevent Brexit would first have to vote against a trade deal and implicitly for exit on WTO terms, in the hope that Parliament would then reverse Article 50 before that two year clock ticked down. If they did so, but Article 50 wasn’t reversed, they’d have backed the very thing they claim to fear the most.

It’s far from guaranteed that the prospect of Brexit on WTO terms would repel MPs from Brexit entirely. As the Prime Minister said yesterday, it’s a viable option for the UK which would be preferable to a bad deal. It’s very much on the table, and the coming months will likely see growing realisation that it isn’t the apocalypse that some pretend.

There are all sorts of “what ifs” used by Continuity Remain to make cancelling Brexit entirely seem like a viable prospect. What if the global economy collapses, what if the EU suddenly tears up its very foundations and abandons free movement, what if the Lib Dems are 30 points ahead in the polls?

In other words, they are relying on various unlikely and inconclusive circumstances to make a tiny window of technical possibility seem like a viable future for their movement. For the minority who are sticking with it to the death, though, that window seems worth pursuing.

So they’re going to try their hardest to keep it open – some for psychological reasons, finding it impossible to adjust to their defeat, and others for reasons of political self-interest, encouraging false hope in order to give the Liberal Democrats a purpose to exist.

Their next step will be to bring a case to the ECJ to try to confirm that Article 50 can be reversed – and to see if that reversal can be done unilaterally by Westminster or if it would require unanimous consent of the EU’s members. They plan to begin proceedings in Dublin later this month.

Such a campaign will be backed by the same team who recently claimed a vote on triggering Article 50 was the silver bullet to stopping Brexit. Just like that case, they may win on the technicalities but they will still lose in practice.