IT’S been a momentous week for the independence movement.

It might only have been one opinion poll, but the news that a majority of Scotland’s voters now support independence has shaken the British parties and the metrocommentariat to the core.

We’ve had the Brexit supporting Guardian columnist Simon Jenkins saying that the British state needs to prepare for Scottish independence. We’ve had panic and denial from SiU and the Tories. We’ve had yet another Broontervention, this time he’s quoted George Orwell on “power hunger tempered by self-deception” – proving that irony isn’t just dead, but smashed into its constituent particles and shot into a black hole to disappear forever from the universe. We’ve even had proof that nominative determinism is indeed an actual thing, as the newly elected leader of Ukip is called Dick Braine.

It’s become abundantly clear that none of the anti-independence parties has any clear idea of how to tackle the rise in support for independence. They are desperately trying to prevent a referendum from taking place, because they know that once it does they’ve already lost. But that’s not a position which is sustainable in the longer term.

We’ve also had the total meltdown of the Labour party in a three-way civil war that has the potential to destroy what’s left of Labour in Scotland. It’s not that Labour doesn’t have a position on Scottish independence, or on Brexit. It’s just that they have several positions simultaneously, all of which contradict one another.

It’s possibly just as well that Richard Leonard has such a low public profile, otherwise he’d be mortified to go out in public in case anyone recognises him. So yes, it has indeed been quite a week.

Opponents of independence have themselves blown up all their best arguments from 2014. They can’t tell us any more that Scotland needs the security and stability of the UK. They can’t insist that only the UK can protect Scotland from political extremism. And they certainly can’t claim that Scotland can only be a part of the EU by rejecting independence.

They’re now left scraping the bottom of the fear barrel with arguments which fall apart the second that even a mildly critical eye is cast over them.

One of the new go-to arguments against independence, once we get past the deeply anti-democratic insistence that Westminster will refuse to “allow” Scotland to have a say, is that since its proving so difficult to extricate the UK from its 40 years’ entanglement with Europe, then it must be even more difficult to extricate Scotland from its 300-year entanglement with the UK.

It’s as though we are to believe the difficulty of ending a political union is a function of the amount of time that political union has lasted, and not a function of the goals and abilities of those doing the leaving.

Essentially what this argument boils down to is that Brexit is hard because the British establishment is a bunch of venal incompetents, therefore Scotland must be even more incompetent.

And because the British establishment is so incompetent, this is somehow an argument for not attempting to negotiate Scottish independence from them. In fact the complete shambles which passes for the British side of Brexit negotiations tends to suggest that even a mediocre Scottish team would negotiate rings around them in independence negotiations.

Nicola Sturgeon is the only grown-up in British politics but the second that Scotland votes Yes she’ll turn into Mark Francois in a skirt.

Comparing Brexit to Scottish independence is specious. The two are very different political objectives. The only real resemblance is that both claim to be unions, although in reality only the EU is worthy of that title. The UK is a union in name only.

The real reasons that Brexit is proving so difficult are two-fold. Firstly there’s the fact that no country has ever left the EU before. There is no road map for doing so, and the British side of the negotiating table is not at all clear on what it is seeking in practical terms.

Wanting to maintain all the benefits of remaining in the EU with none of the costs or downsides is not a viable negotiating position, except if you’re a member of the Conservative party. In the run up to the EU referendum Boris Johnson appeared to believe that the UK could leave the EU, but still have influence over EU decisions. British exceptionalism might play well with the Brexit press, but it doesn’t wash with Brussels.

Secondly, and perhaps even more importantly, the Brexit negotiations are proving so difficult because the UK seeks to achieve mutually contradictory outcomes. Uniquely amongst the countries of the EU, the UK and the Republic of Ireland have an international treaty obligation to maintain open borders with one another. This is the very core of the Good Friday Agreement which underpins peace in Northern Ireland.

On the one hand the UK wants to leave the EU, the single market, and the common customs area so that it can be free to negotiate trade deals involving chlorinated chicken around the globe, and Liz Truss can become a jam salesperson in Beijing. This means that there will have to be checks and controls with the UK’s border with the EU. And on the other hand the UK has a treaty obligation not to have checks and controls with its border with the Irish Republic, which upon Brexit becomes the UK’s border with the EU. Squaring this impossible circle is what makes Brexit so difficult. It’s the pursuit of mutually contradictory objectives.

None of this applies to Scottish independence from the UK. Far from being a one-off unique set of circumstances that have never happened before, there is a well trodden path to independence from the UK, one which over 50 countries have taken. Indeed, the very country which is creating the greatest obstacle to Britain’s desire to have its Brexit cake and to eat it is a country which itself became independent from the UK.

More importantly however, Scotland will not be seeking mutually contradictory objectives in its negotiations with the UK. And we can also hope that the Scottish negotiating team will be rather more realistic than Britain in Brexit, and unencumbered with the British exceptionalism which has created the desire for unicorns, cherries, and never-ending cake. Scottish independence is about escaping the fantasy of exceptionalism and engaging with the real world.

More and more voters in this country have come to realise that there is one side in the independence debate which bases its case on a romatic appeal to nostalgia and an idealised past, on a narrow minded inward looking parochial nationalism, and on a xenophobic rejection the wider world. They’re realising that there’s one side characterised by blind panic, by moral bankruptcy, and by a cheap and shoddy opportunism. And they’re realising that side is the one which opposes independence.