At the beginning of June we shall know if Nigel Farage has made a difference to the outcome of the referendum on Scottish independence, but not before. If he has, it will have been his interventions over last weekend that have provided the ammunition to help sink the nationalist cause; or, more appropriately, the SNP’s version of what independence should mean.

Farage’s opinions on Scottish independence, as reported last weekend have probably gone unnoticed by the vast majority of people in England, Wales and Northern Ireland but, as is typical of the man, they got straight to the heart of the problem of the SNP campaign. I covered it in more detail in The Scotsman, for those interested, so I won’t go over it entirely here, but put simply Farage alleged that Scotland would not win freedom; how could it do so if it remained in the European Union?

It was, Farage argued, a false kind of freedom, a deceit on the electorate – with the EU determining so many laws and so much of what we do, how could that be freedom?

SNP supporters often like to allude to the historically inaccurate Braveheart and Mel Gibson crying “Freedom” but the point is the SNP is not offering a model of independence based on Norway, Iceland or Switzerland – it is offering the freedom of Greece, or Cyprus. Freedom with limitations, freedom with some dependency.

Under SNP proposals Scotland will not only be a member of the European Union (which for sake of argument let us agree is a good thing) but will be a member under worse terms than those obtained by the UK government’s negotiations and renegotiations over the years, and will be expected to sign up to eventual membership of the Euro, Schengen and other aspects of EU membership.

Whatever you think of the EU, and 37 per cent of the Scottish public, according to YouGov wish to be free of it, the SNP is steadfastly against the idea of giving any new Scottish nation a say in EU membership. Unlike, for instance, existing proposals for the rest of the UK to have such a say. So much for the sovereignty of the people, in the context of its draft Scottish constitution, that the SNP likes to talk about.

Freedom for Scottish nationalists is, as Nigel Farage has identified, a very pliable thing.

But Farage went further – a few days later, he challenged Alex Salmond to a public TV debate about EU membership for Scotland, preferably before the May European elections, but most certainly before the independence referendum on 18th September. The answer was silence – apart from dismissive comments by Salmond sidekicks.

Again Farage had identified a weakness that could be exploited.  Salmond and his team keep banging on about having a debate between the First Minister and the Prime Minister, knowing that what they can do is distill Scottish participation in the United Kingdom down to a bitter elixir of toff, Tory Englishman versus avuncular, cheeky Scotsman. A sort of nationalist David and Goliath, only David would be Salmond, Goliath would be Cameron and if nationalists could have their way the post-combat perceptions would be shaped by class warfare, manufactured Scottish victimhood and an appeal to Red Clydeside romanticism.

I can say all of this as a Scotsman whose family were all Labour, my antecedents fought with Bruce at Bannockburn and signed the Declaration of Arbroath. Cameron should avoid any such debate.

But Salmond against Farage? Interesting how that does not appeal to SNP strategists; is it that Farage is thought of as being more a David than a Goliath? More a David than Salmond? Is it that Farage does not appear the stereotype of an English toff? Maybe his anti-establishment credentials are better – maybe his nationalist credentials are better. Maybe Salmond recognises that what Farage says has more than a ring of truth – that the arguments for freedom from Westminster are hollow so long as freedom from Brussels is not included. Or that the SNP arguments about independence are so similar to UKIP’s arguments that Scots might begin to agree with Farage.

Maybe Salmond realises that Farage might at least strengthen his support in Scotland – or, worse still, even win the debate?

The point to all of this is that the SNP is utterly europhile; it believes its own publicity that for a risk-free Scottish independence it must assure the electorate that independence means keeping the Queen, keeping the pound, keeping NATO, keeping open borders – and keeping membership of the European Union.

This is why it denies – in the face of all public advice from the EU itself – that an independent Scotland will have to re-apply for membership. It cannot countenance that it would have to enter into negotiations, which by definition means it would have to concede worse terms than Scotland enjoys as a member of the UK in the EU. Why, Alex Salmond used to say he had legal advice that Scotland would not need to reapply for membership, he even spent taxpayers’ money trying to keep this advice from FOI requests that it be made public – only for it to be revealed by his Deputy that the advice did not exist. It never had. It was a fabrication.

Normally that’s called deceiving the public, but Salmond knows no shame.

For the moment none of this matters. UKIP is dismissed as being unimportant because it does not have any MPs, MSPs or MEPs to give it an elected voice in Scotland. But that could change. After the May EU elections its could, possibly, have an MEP. This would change the political landscape. It is sitting at 10 per cent in the latest EU polls produced by ICM, with 11 per cent thought to be the trigger for winning a Scottish MEP.

With such an achievement no longer could the SNP or its army of cybernats claim that UKIP is irrelevant; it would be official, UKIP would matter in Scotland.

This all has resonance for Conservatives in Scotland and the UK.  If UKIP can win one of the six Scottish EU seats (probably to the cost of the Liberal Democrats) it would be able to say it is a truly UK-wide national party. That would shut a few people up and demand attention as the general election approaches. It would mean that UKIP would be snapping at the Scottish Conservative’s heels. Evidence from Lord Ashcroft’s polling suggest it is already doing this – an elected Scottish MEP would be tangible evidence that it is true.

For me, however, the bigger picture is that Farage has identified a nationalist weakness – the European membership question – and it is something that Scottish Tory leader Ruth Davidson should herself exploit.

What is to stop her saying that a newly independent Scotland should have a referendum on EU membership? Just because Farage is arguing for it does not make it a bad idea – compared to the 15-20 per cent support for Conservatives in Scotland the 37 per cent against EU membership seems fertile ground for her to plough. I have no doubt that if she was to demand such a referendum she would make her popularity in her own party that much stronger and put a great deal of pressure on Alex Salmond at the same time by making the idea more respectable.  Indeed, I suggest that the Labour leader Johann Lamont should do the same.

It would make Salmond look unreasonable, the defender of the establishment, a huge hulk of a man unable, through his own hubris, to see his susceptibility to defeat. It would turn Salmond into Goliath.

Ruth Davidson believes we shall win a No vote, so what has she to lose by suggesting an EU referendum in the event of a Yes vote? What is she waiting for?