IT’S the quietly disapproving stare from colleagues, optimising themselves like crazy; or concerned family members, surveying the current state of your mid-50s carcass. “What ... are you drinking?”

I am drinking a glass of Irn-Bru, thank you very much. Today, it is in diet form. “Diet! So they’ve added aspartame to the ammoniac acid. Why do you have a death wish?”

Questions, questions. But even before I found myself in a loving network of care and aspiration – really, I’m grateful my darlings,

I truly am – I always realised that to gulp publicly Irn-Bru was to be part of something bigger. And baser.

I had a rare full-strength glass of it the other day: the glutinous residue at the back of my throat instantly cast me back into my juddering west-of-Scotland childhood. Not in a happy way.

News that its manufacturer, AG Barr, is preparing to bring out a high-energy-drink version this summer initially prompted

a double-take. Whenever was

Irn-Bru not “high energy”?

Famously competitive as a soft drink with Coca-Cola and Pepsi in the Scottish market, Irn-Bru is one of our lasting imperial legacies.

It’s chastening to realise that the logo for at least half of its existence was “Ba-Bru”, a caricature Indian boy in a turban, who scampered around newspaper cartoon strips like one of Kipling’s natives. His yes-sahib visage once beamed down from a giant ad hoarding at the height of Union Street in Glasgow. Again, not so happy days.

But as a modern Scottish commodity, Irn-Bru does indeed abound with niceties (if you stare into its orange depths long enough). What is the state of Scottish desire, as we glug down our other national drink? What does the amber nectar tell us about what we really want?

We can begin by comparing the Bru with its global rival, and the mind tricks it has employed for well over a century. According to the Slovenian philosopher Slavoj Zizek, there is a compulsion

to enjoy yourself in Coke ads

– a manic celebration of pleasure

for its own sake.

The “it” of “Coke is it!” is something permanently unattainable – a reality that we will never satisfactorily arrive at, so distracted we are by the pleasures on the way.

Zizek says this is why Coke is the ultimate commodity. The drink itself, both its substance and its marketing, is designed not to satisfy your thirst, but to make you thirstier and thirstier.

The 2019 Super Bowl animated ad was a paen to American unity-in-diversity – but all under the one, binding act of drinking Coke. “A Coke Is A Coke” went the strapline. No matter the social arrangement, they ultimately always win.

Zizek may be right about Coke

as the transcendent product-to-beat-all-products. What it’s never shrugged off in its marketing is its sense of itself as health-giving,

an energising fluid.

This is hilarious, given its cocaine content in the early days. It’s now sinister, given what we currently know about the corroding effects of its sweeteners and sugars.

The fascinating thing about Irn-Bru is that its roots are also in this late-19th-century era of energy drinks. On both sides of the Atlantic, these were purveyed to an exhausted, urbanised working class, who nevertheless had some disposable income.

Indeed, as the academic David Leishman uncovered a few years ago, the first “Iron Brew” was trademarked and patented as a “medical tonic” by Maas & Waldstein, a US chemicals company, on January 5, 1901.

The sporting figure that still poses at the heart of the Irn-Bru logo taps into that legacy. But what is fascinating about Irn-Bru’s message in the past few decades is the way that it’s deliberately satirised, even perverted, that aura of health-giving wholesomeness.

It’s been quite a journey towards the current oh-so-scandalous slogan, “Don’t be a can’t, be a can”. Satirising Coke’s relentless positivity was an understandable underdog ad strategy for Irn-Bru in the 1980s. But it was the active embrace of the excessive and taboo-busting which is striking (and which, by contrast, makes you realise how weirdly propagandist Coke is).

What does a soft drinks company do with the fact that there is a rising, year-on-year public health awareness of the toxic, self-destructive nature of its product? One way – bold but clever – is to embrace that very toxicity, but redirect it.

Our everyday relationships are often a burlesque of failure, repression, humiliation, petty vanities, cultural embarrassments. We laugh, painfully, when we are shown how broken and malfunctioning we are.

But what will get us through, according to their recent slogan? Irn-Bru! Yes, it’s mostly men (awkwardly old or young) shown as the consumers on screen. Yet as they quake at their new family member being named “after a long line of Fannys”, or their daughter associating with a British Bulldog of a boyfriend, or their buxom mother transfixing their schoolpals, each saving sip is loaded with a more general significance.

Of course it won’t get you through anything. Indeed, a sudden injection of sugar and caffeine is likely to dispel any calmness you might crave in such situations.

So each hammed-up gulp of Irn-Bru signals very clearly to the audience that this lurid orange drink won’t help us at all – and that they know we know that.

This cynical, maybe even nihilistic mindset, is at the other end of Zizek’s explanations of why we are slaves to consumerism. Here we’re not “desiring to desire”, obscurely gripped by our glossy, unrequitable yearnings. Instead, Irn-Bru asks us to explicitly accept how shabby and incapable we are, and consecrate that with a glass of syrupy, faintly ammoniac crap.

The mesh between Irn-Bru and Scotland’s wider drinking culture only intensifies the desperation. When the company responded to recent government regulation by reducing the sugar content in the average glass of Irn-Bru, public petitions were indeed raised in protest. Why? The petitions wanted to defend the Bru’s powers as a hangover cure. A drunk man looks at his fizzle, yet again.

Were Zizek to turn his stony gaze towards Irn-Bru, he would probably see it as the deepest form of ideology – one that confirms its core message (buy this!) by making us as ironically self-conscious about the selling process as possible. The bans and complaints that their ads regularly trigger would all be part of that super-ironic strategy.

But he might well also celebrate the honesty of Irn-Bru’s awareness, implicit or explicit, of its toxicity. What seems to outrage Zizek more is “a whole series of products deprived of their malignant property: coffee without caffeine, cream without fat, beer without alcohol”... and, I guess, sugary drinks without sugar.

If this reading of Irn Bru works, then it’s another example of Scotland’s modernity – though not, this time, in a good way. “Leave us alone, give us peace, let us be the way we are”, is its underlying ethical message as a commodity.

This recalcitrance pulses through much of the reactionary populism surging across Western society. But in Scotland, haven’t we heard that mantra before? And over and over again? (It was perhaps no surprise that the unlovely Jim Murphy adopted and embraced Irn-Bru as part of his 2014 indyref campaign schtick, plastic bottle in hand

and two crates beneath

his massive feet).

Not only is Irn-Bru sticky, it leaves us stuck – in an unhealthy, self-loathing space. Scotland will never be free until the last can of it is poured down the gullet of the last soft-drinks merchant.

Though don’t ask me to repeat that, fish supper in the other hand, as I next stoat towards the last

train home, as the pishing rain comes down ...