THERESA May heaped another layer of insularity along Britain’s southern shoreline yesterday with a breathtaking but calculated attack in which she accused European politicians and officials of issuing threats to influence the forthcoming General Election.

Standing outside 10 Downing Street on the day campaigning formally began, the Prime Minister lashed out at the “foreign devils” (as Plaid Cymru’s Hywell Williams sardonically put it), as if they were simply expected to shut up even before the Brexit-prompted election gets properly under way.

Mrs May said Britain’s negotiating position in Europe had been misrepresented in the Continental press – a reference to a German newspaper account of her “disastrous” dinner with EU Commission President Jean-Claude Juncker – and she added: “Threats against Britain have been issued by European politicians and officials.”

Furthermore, she added, with a slight hint of conspiracy theory: “All of these acts have been deliberately timed to affect the result of the general election that will take place on the 8th of June.” Her final flourish was to raise the traditional bogeyman of Brussels bureaucrats running roughshod over Blighty.

The most worrying aspect of all this is that Mrs May says nothing unscripted. She chooses her words carefully and, as we are starting to learn in this campaign, carefully avoids situations where spontaneous thought or clarity might break out. While those who prefer to get along with our European neighbours might shudder, wheeling out the bogeyman of Brussels will undoubtedly play to some voters.

And, in party political terms, one effect of this shrill bellicosity could be the weakening even further of the Labour vote in constituencies where Brexit was backed as a cry of desperation from the victims – ironically enough – of Tory policies. On a more optimistic note, it might also weaken Ukip, by the simple expedient of stealing their clothes.

Like the calling of the election itself, prompted partly by internal Conservative differences, her words are politically opportunistic rather than nationally responsible. The future of the country is at stake, but what we get is a Prime Minister posturing as the price of pulling out of Europe becomes clear.

And let’s be clear: if we must have Brexit, no one would wish Mrs May ill in trying to get as good a deal for the country as possible. But it is becoming increasingly clear that, in the absence of Brexit having been properly thought through, a dubious brand of populism is being substituted for a plan.

The picture Mrs May wishes to paint is of a “bloody difficult woman” standing up to a bunch of bureaucrats who wish us nothing but ill. She wants to project herself as what we Scots would call gallus. Certainly, she has a gall. And the galling thing is that all this frantic finger-pointing is occurring before meaningful talks in Europe have even got under way.

When the Prime Minister called this election, she was effectively inviting the nation to interfere in Tory Party politics – something many Scottish voters can only contemplate with a shudder. To then stand up and accuse Europe of interfering is just a little bit rich.