THE Boris Johnson letter is, without putting any gloss on it, offensive mince.

The false assertion about Scotland stagnating is merely a repetition of the current fact-free prejudice at Westminster, which aims to undermine Scotland and its Parliament with the old mantra of us all being “too poor, too wee” and especially “too stupid” to run a country.

It does not even have the benefit of originality, for such belittling of ambition or aspiration has been a key aspect of colonialism throughout history. It is intended to sap self-belief and allow continued dominance by the existing ruling class.

Moreover, it is blindingly obvious to all except those completely submerged in the Westminster bubble (like the current uninspiring crop of Labour leadership candidates) that any assertion of the UK’s God-given superiority and right to rule is not only clearly false but increasingly and visibly ludicrous.

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We should of course be dogged in putting forward the truth which show a worse performance south of the Border in delivering public services from successive UK governments, an absolute nightmare in the UK public finances and complete paralysis in governance as a result of Brexit.

We should also repeatedly showcase our many achievements as a nation whilst determinedly tackling the inevitable

problems of running a complex modern society as we have done for the last almost 13 years.

But we should also laugh at those who know so little of history that they think they can bamboozle us with such old tricks.

We must in addition determine to get even, not mad, when confronting the other patently dishonest assertions in the letter, including the one which claims that there was, and still is, a binding “once in a generation” promise about an indyref.

The National:

Not only was no such unqualified “promise” given outside the hothouse of political rhetoric – a place to which Johnson is no stranger, as his toe-curlingly bad performance at Stormont this week showed – there is also a fundamental constitutional rule that no government can bind its successor.

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We had a minor but interesting example this last week of how such things work.

On Thursday the Scottish Parliament’s Standards, Procedures and Public Appointments Committee, without even a division, agreed to allow councillors who had taken a severance payment and left local government when proportional representation was introduced in 2007 to stand again for election if they wished.

Not only had those councillors agreed in writing never to run again in return for compensation but the then deputy minister for public services in the Scottish Executive, Tavish Scott, told the Scottish Parliament in the final debate on the issue that “we are not in the business of letting councillors benefit from a severance payment and then stand again” and the Parliament backed his “binding promise” by 80 votes to 29.

Times change, circumstances change, politics changes and one of the masters of the volte-face is Boris Johnson himself. The man in favour of remaining in the EU becomes the leader of the campaign to leave. The candidate for leadership who says that the UK will Brexit on October 31, no ifs, no buts then meekly accepts a further three-month delay.

And the hero who will defend the Union to his dying day does the dirty on his political pals, the DUP, without a second thought.

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In the world of Boris Johnson any opinion, conviction or promise can and will be abandoned except one. Typically for Johnson, the master of untruth, that one was made neither by him or anyone else.

Because he knows he must avoid at any cost the possibility of Scotland choosing a different future he peddles the desperate lie that there is such a thing as a generational promise, that it applies in this case and moreover it has more weight than anything any other politician has said in the last century.

That is all such a threadbare trick that it cannot and will not hold.

Indeed we should take heart from it.

In December the Scottish people voted for the right to choose their own future. The First Minister eloquently outlined the case for it in her presentation just before Christmas.

The document that the Scottish Government then submitted in evidence for it was well-argued and well-sourced.

In response, all our country got back this week was five badly written paragraphs full of inaccuracies, false assertions and weak as water political arguments.

And it is that difference, in the end, which will make all the difference.