HUMZA Yousaf, health secretary and potential First Minister (yup), appeared to suggest the other day that the UK Government was “foreign” which led to the Tories saying he was being inflammatory and polarising and we know how this goes don’t we? We’ve been here before with the SNP and the Tories. We’ve danced this particular do-si-do many times.

But Mr Yousaf’s use of that particular word – foreign – is interesting and a bit of an etymological comeback. Foreign is the kind of word you’d maybe hear your grandparents use in the 70s about German cars or Spanish food; it has the ring of post-war condemnation about it and was often followed by words like “muck” or “invasion”. More recently, most of us have tried to use it with care.

So, the fact Mr Yousaf bunged the word into one of the leadership debates is revealing, although we need to be careful about what he actually said. Asked about gender reform, he confirmed he would go to court over the UK block on the Scottish Government’s bill. He then added: “If we were independent, we would not have a foreign government, for example, coming in and vetoing our legislation."

Obviously Mr Yousaf used the phrase “if we were independent” which means in theory he was talking about post-independence. But there’s no doubt some nationalists already see the UK Government as foreign in the sense of not being a legitimate government of Scotland – I’ve heard some of them refer to “the English government” and “English PM” for example.

I also sometimes wonder whether this kind of stuff is part of what might be called “foreignization”. Obviously, we now look to Holyrood first for a lot of the issues we care about – in that sense Edinburgh has become more “home” and London more “foreign”. And if this is foreignization – an increased feeling of England being different – then part of it could be due to an effort by some in the SNP to use words that emphasise difference and part of it could be just the way things have gone post-devolution.

But the bigger and more important part is the fact that the use of “foreign” in respect of England is correct in some ways and always has been, which complicates things. The Tories say the UK Government governs in Scotland so it cannot be foreign and you get the sense that what they really crave is a monoculture that never really existed. In fact, the UK is made up of countries which are, and always have been, different to each other; countries which are foreign.

Alex Salmond, a former First Minister (yup), made this point at the recent independence debate at the Oxford Union. Scotland had hundreds of years of history as an independent nation before the treaty of union, he said, and it’s one of the most distinctive national entities in Europe. So if Scotland’s not a real nation, then there’s hardly a real nation on earth.

Mr Salmond is right of course and even in the long-gone days before devolution, I was aware of it – in school doing Scottish Highers or at university studying Scots law. We’ve always had distinctive systems and a separate identity and to that extent the other nations of the UK have always been foreign. For that reason, I think I can forgive Mr Yousaf his slip-up. We aren’t being foreignized because we’re foreign already.

What really matters here though is that Scottish identity, and the relative foreignness of England in some ways, is something that’s felt not just by nationalists but unionists too. The difference with unionists is they don’t then confuse the question of identity or foreignness with the question of independence.

Alastair Campbell spotted it long ago. I’ve been reading his diaries from his time in the Blair government and in 1999 he said something interesting about the SNP’s efforts to establish itself as “Scotland’s party”. This was risky for Labour (as we later found out) but Mr Campbell was also able to see that the best way to take on the SNP wasn’t on identity, it was on the costs of separatism and it still applies. I'm very comfortable with the fact that in some ways England is foreign. But the point is I’m also comfortable with asking the same question over and over again on independence: what would the cost be?