For the last 20 years, Scotland has been labouring under a lie. A lie that is so offensive that seemingly no-one dare mention it. A lie that has condemned it to perpetual one-party rule, even while that one party is bereft of either ambition or basic competence. For years, I have waited in vain for any Scottish politician to speak the truth to their compatriots, yet none ever do. The lie is too big, the offence is too great. This is the lie: “Scottish independence is possible.”

In an economy like Scotland’s, cutting itself off from the financial lifeline of the Union would set off a chain reaction

Many will scoff at this, arguing that it is plainly possible, that any country can be independent. Well, true enough, in the same way that I could be appointed captain of the Chinese synchronised swimming team. An awful lot of people would have to willingly take decisions that would not only be profoundly against their interests, but in flat contradiction to human nature.

It is the standard position of the Unionist politician to confess that, of course, independence would be possible, but that it would be merely undesirable. I suspect that most of them know the truth but are afraid to offend certain members of such a notoriously thrawn populous as exists North of the border. It is the same logic as deciding not to tell your daughter that her boyfriend is a waste of blood and organs because it would just make her dig her heels in all the more. Well, the difference is that you hope your daughter will hopefully come to the realisation herself with experience. There would be no such opportunity for a change of heart should Scotland vote for independence.

Here are the facts as they stand (and, as per the revealed preference of the SNP, I shall use the figures excluding North Sea oil). The latest financial update from Government Expenditure and Revenue Scotland (GERS) shows that government spending now accounts for 55.4 per cent of economic activity, far greater than the 44 per cent for the UK as a whole. By way of comparison, government spending in the USSR in the 1980s accounted for just 52 per cent of GDP. Somehow, a modern, open economy has achieved Soviet levels of state preponderance.

On top of that, Scotland’s budget deficit is now 14.3 per cent of GDP compared to 5.1 per cent for the UK. Taken together, that means that fully 26 per cent of government spending comes from revenue not raised in Scotland. In the event of a vote for independence, that number would become painfully real, bewilderingly fast. Does anyone suppose that taxpayers in the rest of the UK would continue to support vast fiscal transfers to a Scotland that’s sticking two fingers up while walking out the door?

Think about what an impact this would have. Millions of public sector workers, pensioners and welfare recipients could have their income cut by a quarter (as happened in Greece after the 2008 crash). For most people, a quarter of their income represents virtually all of their discretionary expenditure. A huge swathe of the middle class would find themselves operating at a subsistence level. There would be no money for simple luxuries, meals out, take-away coffees, holidays, or new mobile phones every year.

Think about what that would do to the ever-diminishing part of the economy represented by the private sector in Scotland, including restaurants, cafés, hotels and shops. Thousands more people could find themselves unemployed, living in a state that has little viable capacity to support them. Mortgages will go unpaid, on properties whose value has collapsed, leaving people trapped in negative equity. People might even wake up to find they are now being paid in sharply devalued groats but with their debts still denominated in Sterling. There would be no market for Scottish government bonds in such circumstances, so no budget deficit at all would be possible.

High earners would flee, to avoid the cripplingly high taxes that a desperate state would impose. Good luck finding a consultant cardiologist, an experienced software engineer or even a qualified accountant. Tax revenues would by now be in a vicious spiral downwards. There would be a flight of the young and ambitious across the border. Rural and island communities would become unsustainable (“the Swinney clearances?”). It would be as close to total societal collapse as has ever occurred in a modern developed country.

Do I exaggerate? Only to the extent that there is no way that public consent for independence would last a fortnight once the reality became clear. Consider that Rachel Reeves faced a rebellion over her plans to cut £5 billion out of future growth of welfare – a mere 0.4 per cent of government expenditure. Is anyone seriously telling me that cutting a quarter out of current spending is a simple first step on the route to sunlit uplands, cheered along by the liberated masses?

In an economy like Scotland’s, cutting itself off from the financial lifeline of the Union would set off a chain reaction that would utterly devastate the economy and the lives of every single person living there.

It’s time to stop lying. Independence is impossible and, with that, the SNP has nothing left to offer. Scotland needs a new government.