IT is a feeling familiar to anyone who has suffered toothache or opted to spend Christmas with the in-laws. That longing for something to be over. A yearning that starts off small and grows until the sufferer can think of nothing else but release, sweet release.

Pull that tooth. Book an earlier flight home. Do something, anything, but make “it” stop, it being the pain, the boredom, or in this case, Brexit.

There has been a certain hysteria in Westminster this week, fuelled by the knowledge that one way or another Brexit is approaching the end game.

Wholly understandable given the divisions the process has caused and the way it has brought politics to a standstill. But there is delusion at work here, too. Regardless of what happens in the coming days, Brexit is not going to be over any time soon. We are just at the start of a process that might still be playing out 30 years from now. There, hasn't that cheered you up?

Brexit has set some obvious, and not so obvious, precedents and the response to these will determine much of what comes after. Take, for example, what it has done to the way politics is conducted.

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Amber Rudd, former Work and Pensions Secretary, said this week she detected a “whiff of sexism” in the way Theresa May's plan was ditched for Boris Johnson's. May was collegiate and consensual, he was macho and sacked people. Taking Ms Rudd’s theory further, Boris Johnson’s rise in the polls could be seen as validating his behaviour, setting a “might is right” tone for the future.

There is something to such notions, but not much. The modern age of the strongman in politics started three years ago with Donald Trump. Boris Johnson is just yet another version.

A greater difficulty in accepting Ms Rudd’s theory of sexism at work concerns Mrs May herself. Though one could feel sympathy on a purely human level for the pressure she was placed under, her uselessness had nothing to do with her sex. She was a classic case of the wrong person being in a wretchedly demanding job at the worst time.

When the history of Brexit comes to be written, there are plenty of women who could be said to have played crucial roles, sexism be damned. Among them are German Chancellor Angela Merkel (for not rising to the baiting of the extreme Leavers), Joanna Cherry of the SNP (for challenging the Johnson administration’s proroguing of parliament in the courts), and Lady Hale, president of the Supreme Court, whose ruling on parliamentary sovereignty will still be quoted generations from now.

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In any case, Mr Johnson’s chest-beating, deadline waving, and itchy trigger finger has worked against him. He lost his majority and the ticking clock, the very thing Brexiteers told him to deploy in negotiations, has instead been turned in his direction.

It is not Emmanuel Macron who said he would rather be “dead in a ditch” than countenance another extension to a deadline. Michel Barnier has not committed to achieving Brexit by October 31 “come what may”.

Even if Mr Johnson does scrape a deal in Brussels his problems could be just beginning. Any agreement must be turned into law, and bills can be amended. Now 23 MPs short of a majority, the Government will be vulnerable at every twist and turn to amendments being proposed and voted on.

Maddy Thimont Jack, a senior researcher at the Institute for Government think tank, told the Today programme yesterday that similar pieces of long, complex, EU-related legislation, the Lisbon Treaty and the Maastricht Treaty, had 88 votes and 120 votes on them respectively. Plenty of opportunities for ambushes, then.

A more immediate concern to those who wish to see a clean exit from the EU is that MPs will support the deal but only if there is a confirmatory referendum tied to it. Again, this has the potential to lay traps for the future, not least for the SNP and supporters of an indyref2 in general. There has always been a fundamental flaw with the SNP’s support for a second vote on EU membership.

If a vote on Brexit can be overturned in just three years, what is to stop the same happening with a vote for Scottish independence?

Certainly, you could argue that voters in 2016 did not have all the information to hand to make an informed choice, or were straight out lied to, but the same arguments could be deployed in time against a vote for independence.

We know work is being done on another blueprint for independence, but times and circumstances change, and I do not recall the claims in the last door-stopper of a White Paper having a long shelf life. All of these caveats would also apply to a vote against independence. Unless, of course, the winning side had to reach a certain percentage, but that, as in 1979, would be controversial.

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If it does nothing else, the Johnson plan has confirmed that a border is a border, and that they matter. Hard or soft, still a border. In the sea, monitored by technology, checks carried out in remote centres, still a border. Nicola Sturgeon, in acknowledging recently that there could be a hard border between an independent Scotland and the rest of the UK, is to be commended for her clarity and honesty. But the First Minister is mistaken if she thinks raising the matter this early on will allow voters to at least become accustomed to the possibility. The very notion of a border is problematic now, and will only become more so if it looks like happening.

As it might. Brexit has confirmed what was already known about the EU: that it is a formidable opponent when it believes its interests and architecture are being threatened. Much of the EU’s approach to Brexit has been about setting an example, pour encourager les autres. Having expended so much time, energy, and money on Brexit, the EU will be in no mood to compromise with any other nation wanting out, or, in the case of a post-Brexit independent Scotland, in. Special treatment would be highly unlikely.

Which brings us back to where we came in, with Brexit fatigue. The last three years might have persuaded increasing numbers of Scots that they would be better off out of the UK and in the EU, as a poll at the weekend suggested. Yet how many, if it comes to it, will see more years of upheaval as a price worth paying for that? There may not be any choice in the end, but let us not pretend it will be easy, or quick.