It is time we all had a long hard think about Scotland's "ethnic" nationalists; the British ones, that is.

Hardline ultra-unionism, in my opinion, is starting to creep in to our national political life.

And it is, for me, every bit as ugly and damaging as the "blood and soil" chauvinism found on the fringes of the independence movement.

Yet, somehow, Unionists go unchallenged on views, for example, about minority Scottish languages that would be a clear flag for far-right nationalism anywhere else in Europe.

Plenty of others have highlighted the uglier side of the independence movement, its boorish, eccentric and counter-productive "cybernats", for example.

What fascinates me are some of the things that enrage hardline Unionists:

Gaelic and Scots, especially when written in public or associated with any symbol of authority

Potential Scottish public displays of the Irish tricolour or what is seen as excessive use of the Saltire by public bodies

The Scottish Six, or any suggestion that the BBC or another broadcaster should cover more international news from a Scottish perspective

Scotland pursuing its own diplomatic course or opening its own "embassies" overseas.

Many will have encountered visceral anger about these issues. Why do these relatively modest things generate so much passion? Well, because they suggest there is something distinctive about Scotland and that irks.

Take languages. For decades there has been consensus about the importance of supporting Gaelic.

Yet the toughest of British nationalists spit bile at the very idea of a Gaelic school or (cost-free) road sign outside the Highlands and Islands, which they make sound like some kind of reservation Gaels should not leave. The rhetoric gets dangerous, in my view.

But there is nothing unusual about far-right intolerance of minority languages.

The same raw nationalistic fury erupted elsewhere in Europe when neglected or oppressed languages appeared on road signs or, worse, police uniforms.

This same kind of weirdly disproportionate anger re-emerged in the row about the Scottish Six.

The BBC is proposing a modest extension to its Scottish news of an evening so that, among other things, world and UK events can be reported from a Scottish perspective.

However, the angriest of British nationalists can't tolerate the idea that the Scottish view of the world might, ever so slightly, differ from London's.

Tory take on Scottish Six: "descent in to inward-looking parochialism"

They also can't bear the idea of Holyrood politicians having a different view on foreign policy to the UK's, hence rage of that Dublin office announced by the Scottish government recently.

Well, as we all know, the line between foreign affairs (reserved) and domestic ones (devolved) is pretty fuzzy.

But don't expect a relaxed acknowledgement of this from ultra-Unionists.

Fury at Scottish foreign policy comes straight from the playbook of anti-separatist nationalism across the continent.

Spain's government, in a kind of horrible reminder of counter-productive ultra-unionism, recently moved to shut down Catalonia's foreign ministry.

I think the this newly emboldened breed of British nationalists - who resent any notion of Scottish distinctiveness - present a problem for mainstream Unionism.

Why? Because they threaten the very basis of the devolution settlement that is somehow holding our multi-national island state together. They threaten the consensus that Scotland is different.

Read More: Scots-speaking parts of Scotland among most unionist, Herald research shows.