IF there’s an expression I have grown to resent over time it’s the dull metaphor – “two cheeks of the same erse”.

Much as I appreciate the raw and visceral earthiness of the expression, its underlying meaning drives me to distraction, simply because it is rarely if ever true. I first heard the term being used by George ­Galloway, whose collapse in credibility over the years has probably soured me, but it goes much deeper than that, much deeper.

I cannot claim to be expert on the geometry of posterior, but the expression seems to presume that the two “erses” are equally proportioned. That is where the metaphor falls flat and leaves its users making false equivalences between two very differently weighted phenomena.

Take the Labour Party and the Conservative Party. There can be no doubt that they currently oppose Scottish ­independence and so often attract the two-cheeks put down. But are they equivalent? Really?

One overwhelming difference between the two is that the Conservatives have been in power across most of my lifetime. It was the Labour Party, motivated by a fairer democracy of representation, that introduced the referendum which led to the Scottish people voting overwhelmingly for a Scottish Parliament.

The Labour Party have across time been architects and then defenders of the welfare state. They are less likely to be drawn from the land-owning aristocracy or even the modern banking elite. They are two quite different parties, one founded to advance workers’ rights the other bound to restrict them. It was Labour that brought Nelson Mandela to Glasgow at a time when the zealots of Conservatives wanted him hanged for terrorism.

They may well be “erses” and some members of the Labour Party wear the ­description like a crown, but to suggest that the Labour Party are the equals of the Tories is to seriously misrepresent ­political ­history.

One of Labour’s most significant ­contradictions and the one that is at the root cause of their current failings, has been resistance to change, whilst trying to reverse the break-up of Britain. It has not served them well.

The Labour Party are a shadow of their former selves in Scotland. They bicker about almost everything the SNP proposes, whilst their own party members cheer on similar legislation where they are in power in Wales.

As for Northern Ireland a frontline of the Unionism that the Labour Party ­defends, they don’t even field candidates, and are curiously silent on issues that are advancing the decline of Britain but are of no great electoral value.

Another area where the two-cheeks metaphor raises its ugly rear end is in social media where it plays a role in the battlefield of arguments. In Scotland “two cheeks of the same erse” is often ­deployed when an argument has been ­reduced to an either/or simplicity.

Those that despise online debate point to reductive binary arguments that ­distil complexity down to a choice of two extremes.

So, Unionists of whatever sociopolitical character are two cheeks, Old Firm fans are frequently dismissed as two cheeks and, despite the mountainous complexity of re-joining the European Union that too is about Leave and Remain, compressed into a corset designed to constrain the gluteus maximus of wider debate.

I hold passionate views but wake up every day hoping they can be enriched or made more complex, not reduced to simplicity. More than anything I like the debates that try to “imagine a country” and sketch out Scotland’s future. How can this place we live in be better, more ambitious and most of all be self-determining?

Nothing irks me more in public ­discourse than the constricting metaphor of two cheeks. It is an analogy that has not served Scotland well. It creates ­enemies where friends might lurk, it ­polarises opinion when winning people over to ­independence is crucial, and it elevates ­serious debate into knockabout farce when greater complexity is most welcome.

This week I have been watching Euro 2020. It’s a great petri dish in which to ­inspect national patriotism and the ­increasing neediness of ­Unionist ­commentators to corral people into ­supporting England.

This sad parade of insecurity comes around every couple of years, dressed up in a binary falsehood that you either support England or you hate England. Trust me there are many more grains of sand on the beach than that.

THEN there’s the royal family. If you were to wander the corridors of Buckingham Palace with a banjo you would not be short of erses to hit. But even within the beating heart of the royal family it is unfair to portray them each as equally vile.

This week as part of their charm offensive in Scotland, the Palace declared that the Queen had visited Edinburgh during #RoyalWeek2021, a concept that had passed me by despite but which we are assured it being a time-honoured tradition.

As part of her punter friendly visit, the Queen opened a new Irn-Bru processing line in Cumbernauld. Her son, the Earl of Strathearn, did not hang around too long he had to bolt back to Wembley to cheer England against Germany. He was ­possibly the only person within a ­hundred mile of earldom near Aberthuven that was so vocal in his support.

I am not a fan of unelected monarchies and cringe at the way that the media genuflects in their presence. Yet even in that most combustible of debates it is far from being an either/or question. The fundamental problem with that specific cheek, is that there are far too many erses.

Although the media, led by the BBC seems to be supine in the face of royalty, even they accept that there is a problem at the heart of all of this.

The Queen is now 95-year-old and her husband, Prince Phillip, has recently died. Whilst her stoic widowhood has been ­admired by many, it can no longer ­disguise looming problems for the House of Windsor.

First and foremost, the next generation are unpopular even in the most royalist households in the English shires. Prince Andrew, a monarch for whom the word erse, seems to have been invented is still hiding from the FBI in the fallout of the Jeffrey Epstein scandal. His ill-advised television interview to clear his name, turned an already unpopular man into a cosseted pariah.

Prince Charles, and his wife the ­Duchess of Cornwall, are marginally more popular but neither has fully cleansed themselves of the events leading to the death of Diana Princess of Wales.

It is Diana’s sons that stand the greatest chance of credible inheritance. One has already bolted to Los Angeles on the Instagram circuit, leaving the other, balding, and shorn of much of the youthful charisma, to carry the burden of expectation.

The royal family desperately needs a succession strategy and an accompanying narrative that manages to negotiate traditional inheritance and modern ­popularity. That will not be easy. The one binding feature that has kept the royal family credible is stultifying deference: our knowing subservience to a bloodline and an unelected figurehead.

Every credible survey that measures the popularity of the royal family exposes a deep and impending crisis. Whilst the concept may still have credibility the characters do not.

Last week, the media assured us that Royal Week was about keeping Britain ­together, it may well have been much more desperate than that.

It was more probably about keeping the show on the road.