As Cop26 draws to a close, the climate summit’s big-name sponsors have been left scratching their heads as to how the plucky Scottish fizzy drink Irn-Bru managed to steal the limelight in the marketing ambush of the year.

The status of the bright orange drink as the summit’s surprise curiosity made global headlines earlier this week when the US congresswoman Alexandria Ocasio-Cortez posted an Instagram video of herself praising the beverage after having her first taste.

AOC, as she is known, was urged to try the drink by the Scottish first minister, Nicola Sturgeon, who handed her distinguished foreign guest a can on her arrival in Glasgow and then posted a selfie of the moment on Twitter.

The subsequent social media explosion and acres of online and print column inches have given the brand a golden marketing moment that millions of pounds of advertising couldn’t hope to emulate.

“It is priceless getting this sort of media attention,” says Colin Kennedy, the chief executive of content creation agency Redwood. “Brands very rarely manage to create these sorts of headlines. Sturgeon and AOC have emerged as two ambassadors for Irn-Bru in what looks like a completely authentic, unstaged moment.”

While official sponsors from Sky to Sainsbury’s paid millions to burnish their green credentials by being featured at the event, and populated panels with executives, Irn-Bru leveraged its status as a national champion to sew up the on-site fizzy drink market.

Its parent company, AG Barr, had an existing deal in place that shut out rivals such as Coke and Pepsi, to make Irn-Bru – often referred to as Scotland’s other national drink (after whisky) – the only fizzy drink available at the SEC and SSE Hydro convention centres in Glasgow used during Cop26. The deal with Glasgow Life, which operates the venues, made AG Barr the exclusive soft drink and water supplier.

“That was the clever bit of marketing: availability at the venue,” says Kennedy. “But Irn-Bru is also a kind of proxy for the national drink of Scotland, and it comes with the support of people like Sturgeon.”

While almost impossible to estimate, the value of the media coverage would run into the millions for Irn-Bru. A single ad slot on the front page of a UK national newspaper can run to about £15,000, and up to £300,000 for a “wrap” of the Sun, according to media buyers. Buying the digital ad space to reach the millions of readers of the coverage, as well as viewers of AOC’s video, would have run to hundreds of thousands of pounds media spend.

However, the coverage has been through editorial content, considered to be much more engaging and therefore more valuable than running ads. Experts say the free coverage is worth several million pounds at least in equivalent media value if such a publicity stunt had been achieved by a PR agency.

Aside from Donald Trump, who banned it from his luxury golf resort in Turnberry in 2018, Irn-Bru has a legion of high-profile supporters. Andy Murray eschewed other beverage options to toast his 2012 US Open victory with it, the late Sir Sean Connery reportedly chose a crate of Irn-Bru to represent Scotland at an exhibit at the Museum of Scotland, and in June the Queen and the Duke of Cambridge, Prince William, paid a visit to a new processing factory.

Launched in 1901, supposedly as an alternative to beer for steelworkers building Glasgow station, it was originally called Iron Brew but changed to Irn-Bru in 1946 – a decision forced on AG Barr, because the drink isn’t actually brewed.

The beverage, which has its own tartan, joins the likes of Coca-Cola and KFC in having a secret recipe – in Irn-Bru’s case, 32 ingredients known by as few as three people.

Despite being a brand giant in Scotland, supposedly the only country in the world where Coke is available – though not the most popular fizzy drink – its carefully cultivated image as a brand challenger makes it palatable for political figures to promote.

“Would they have been seen grabbing Coca-Cola or a 7UP and posting like that, no chance,” says Mark Borkowski, a PR expert. “They see the quirkiness of Irn-Bru as an emblem of Scotland: it’s OK to like it. And like Marmite, it is an acquired taste – those sorts of products always get strong reactions.” Irn-Bru’s Instagram account runs with the line “Let’s Just Agree It Tastes Like Magic”.

Despite the priceless publicity, AG Barr’s share price has remained fairly flat during the Glasgow gathering. The group – which owns or licenses 16 brands including Rubicon, Snapple and Bundaberg – is listed on the London Stock Exchange, but its largest shareholder is still Robin Barr, the former chairman and great-grandson of the founder. The company made £227m in revenues in the year to 24 January 2021, but is not a particularly global business, saying that it “sells mainly to customers in the UK with some international sales”.

“It’s been phenomenal to give people from across the globe a unique taste of Irn-Bru during Cop26,” a spokesperson for the company said. However, it is mindful that while the free publicity makes for a marketing dream it musn’t be seen to be “overshadowing or trivialising the importance of the conference for its own gain”.

While the publicity has not moved the share price, the orange stuff seems to have won some new fans among a select group of green grandees.