SADLY I suspect Sadiq Khan is too arrogant to realise just how much damage he’s done. By insulting half the Scottish electorate – the progressive half – he’s blown a big hole in Scottish Labour’s future with an election just months away. That’s bad for his party, and, right now, it’s bad for Scottish politics.

But, for me, the cost of his remarks goes far beyond the electoral future of Labour. Far worse, his rant makes it much harder to start a serious national conversation about the very real problem of racism in Scotland. Scottish nationalism isn’t racist; and it’s doubly not racist if we judge it by the standards set by Khan’s preferred model of New Labour with its “British jobs for British workers”.

But Scotland remains a racist society, and the liberal consensus around “civic nationalism” can be a barrier to challenging this. Khan has set himself up as a perfect straw man for the No Problem Here brigade who see Scotland as a multicultural paradise of inclusion and diversity.

When it comes to this question, I’m caught between two radically conflicting pictures. In the Holyrood village and the social media bubble, there’s a sort of obligatory political correctness that looks askance at Trump and Brexit and celebrates what they see as a well-behaved polity that has conquered the evils of anti-immigrant populism.

However, the Scotland depicted by my black and ethnic minority friends is far grittier, far more hard-boiled and far closer to the realities of England. They describe a psychology of constant wariness which sometimes edges over into outright terror. One Scottish BME women I’ve worked with for years told me that, as a white person, I’ll “never have to experience the wrath of a racist who only sees your skin colour and wants to smack the fuck out of you”. And she’s right.

Another friend of mine is mixed race but could “pass” for white. Often, Scottish hard men banter with him as one of the guys. This unusual intimacy allows him to observe our culture of casual racism at first hand, free from the platitudes of professional politics and journalism.

Recently, he was chatting to the man who delivers his online grocery shopping. The driver confided to my friend that most people in the area didn’t have their shopping delivered, because “that lot”, i.e. refugees, “came here” and “had everything handed to them on a plate”. Unfortunately for the driver, he’d entrusted his racist banter to the wrong man, and he found himself chased off the estate. Maybe next time he’ll think twice. But clearly he was accustomed to a culture of tough talk where such comments are as natural as chatting about the weather.

These are the everyday realities of being black minority ethnic (BME) in Scotland. There are, of course, far more serious examples. Take the case of Surjit Singh Chhokar, murdered in 1998, and the family’s decades long struggle against a corrupt Scottish legal system that Aamer Anwar described as a “gentleman’s colonial club”. Take Sheku Bayoh, who died after being restrained by a Fife policeman with a history of violence and racism. Take the series of racist attacks in Sighthill, Glasgow, that ended in two asylum seekers being stabbed only a decade or so ago.

Overall, between 2000 and 2013, the per capita rate of suspected racist murders was higher in Scotland than elsewhere in the UK, according to one estimate by the Coalition for Racial Equality and Rights.

Academics and anti-racist activists have long questioned the received wisdom of Scotland as a progressive paradise. Since devolution, social scientists have been collecting a mountain of data on these topics.

Most of the evidence leads to a consistent conclusion about Scottish attitudes. North of the Border, we are slightly less racist than the rest of the UK, but only by a small margin. A 2014 survey found that one-in-four Scottish people admit to racist attitudes, compared to one-in-three English people. The differences are notable, but they’re not enough to say we’ve got “no problem here”.

There are two clear and decisive differences between Scotland and the rest of the UK. Number one, Holyrood politics isn’t poisoned by racism like Westminster debate. For now, there’s a broad consensus about the need to avoid inflammatory racist rhetoric.

However, this thought needs qualified. Just because Scottish politicians don’t spit venomous rhetoric doesn’t mean they aren’t benefitting from racist sentiment. Undoubtedly the Tory vote in Scotland has been boosted by racism: Tories here might be more liberal, but tabloid populism has an audience in Scotland, and they are the obvious beneficiaries when racism is on the rise.

When Scotland becomes independent, it will have control over borders. A strong Scottish Tory Party will be an obvious magnet for populists who want to exploit racist attitudes to boost their vote. At that point, the SNP will be faced with a dilemma: do they “triangulate” to stay in power and keep racism within moderate bounds? Or do they stick to their commitments to create a different consensus in Scotland?

Nonetheless, for now, Scottish politics remains an uncontaminated bubble. Judged against what’s happening in England, it’s a good thing – but can it last?

A second distinct feature of Scotland is that the implicit “whiteness” of our national identity has never been fundamentally challenged. That’s partly because most of our historical immigration came from Ireland. As a result, Scotland’s BME population is just 4 per cent, compared to 14 per cent UK-wide.

In England, there are many BME sportspeople, BME celebrities and BME authority figures. We have those things in Scotland too, but to a far smaller extent.

In some areas, there’s dramatic under-representation. A study of the last local elections found that there are no BME councillors at all in 25 of Scotland’s 32 local authorities. Add in gender, and the figures are even more worrying. Only four BME women were elected as councillors in the last study. This applies in all areas of authority in Scotland, from politics to the police to the arts.

It’s time we had a grown-up debate about these issues. But the blinkers of unionism versus nationalism often makes this next-to impossible. Sadiq Khan’s intervention threatens to roll back years of progress in challenging racism north of the Border. Just like the No Problem Here brigade, his comments are unconstructive, divisive and misinformed.

Let’s not rise to his bait. After independence, we can do better than the poisonous political and media standards set by Westminster. Of course it can. But there are no guarantees. We’ll have to get tougher at challenging everyday racism, and we can’t keep blaming it on London. We’ll also need to challenge naivety in a political class who still live in a disconnected bubble. Only then can we definitely say we’re taking a different road from Brexit Britain.