PEPSI has become  the latest brand to make the biggest mistake  in the business book – failing to recognise its audience. Its new multi-million dollar advert, featuring American model and reality TV star Kendall Jenner giving a can of the drink to a police officer during a protest, was pulled 48 hours after release.

It has been hailed as possibly the worst TV ad of all time – quite the credit when you consider some of the other disastrous ads we’ve witnessed over the years, including Sony PlayStation White, which depicted a white woman fiercely gripping a black woman’s face, and Bloomingdale’s catalogue ad for Rebecca Minkoff merchandise which suggested a man might want to spike the drink of a female friend.

But how do brands still manage to make blunders like this when they have decades of experience in getting to know their customers.? PR expert Scott Douglas says Pepsi’s decision  to go full tilt after a millennial audience isn’t just culturally tone deaf, but also wilfully customer age blind.  Douglas, co-founder of Edinburgh-based public relations agency Holyrood PR, says Pepsi has all the research in the world that tells them their demographic skews older, and that those older consumers are the ones with money to burn.

And he doesn’t mince his words when he describes the ad as “vapid, self-indulgent patronising, cringe worthy, glossily soulless guff”. Douglas said: “While this has caused controversy on many fronts (foremost for hijacking  and trivialising the Black Lives Matter campaign) what really bugged me about it was just how ageist it is.

“This ad has been derided for too carefully representing every skin tone imaginable. But try to find anyone over 40? You’ll be lucky. Over 50? Not a hope.”

Over-50s make up one-third of the UK’s population and hold  80 per cent of the wealth. Their consumer spending has grown on by 4.4 per cent each year for the past decade, while the figure is 1.2 per cent for under-50s.

More than 60 per cent of new cars sold in the UK are bought by over-50s. And Douglas points out that research in December showed Pepsi’s biggest audience is over-65s, while arch-rival Coke’s is 35-44, with both under represented among 18 to 24-year-olds).

“You won’t see over-50s in ads, despite the fact people in that age group are wealthy, confident, vigorous and healthy,” Douglas said. “This ridiculous ad got through because advertising agencies are full of people who think everyone wants to be like them: right on, uber cool –and under-30. Unfortunately the obsession with ‘youth’ means creative teams lack experience, depth ... and the kind of wisdom that only comes with age.”

“Any campaign for any client should start by asking what the client wants to achieve? It’s impossible to figure out what Pepsi hoped to achieve with this dog’s dinner - or how they hope to gauge and measure that.

“You simply can’t mitigate against such determined stupidity.”

The lesson to be learned is clear - ignore your true audience at your peril.

Michelle Rodger is a communications consultant