Hair, teeth and ears all present and correct: is Iain Duncan Smith too good to be true? Photograph: ITV/REX Shutterstock

Last week, the Department for Work and Pensions tsar, Iain Duncan Smith, was revealed to have fabricated a pamphlet featuring two entirely fictitious former benefit claimants, using Conservative party stationery cupboard scissors and an adhesive he emits from a weeping gland in his own perineum.

The level of happiness in the workshy duo’s photos, in which they beamed about the just withdrawal of their benefits, was utterly convincing. I wondered if the models featured had been told to imagine seeing Iain Duncan Smith fall into a wood chipper while wearing Michael Gove as a novelty meat hat.

And I realised that in so doing, I had fulfilled a Daily Telegraph reader’s stereotyping of a modern comedian as someone who thinks images of unacceptable physical violence against public hate figures constitute a substitute for genuine wit.

But much as I would love to see the Conservatives make some catastrophic public relations error that would permanently damage their so far untarnished reputation, I was not sure that Sarah and Zacgate was it.

There is, of course, a long history of public campaigns featuring ludicrous and fictitious characters designed to convey messages to the proletariat. Indeed, the last Labour election effort featured an unlikely puppet character called Ed, who wrote his thoughts in big letters on a semi-portable gravestone.

Historically, our masters have always imagined we lowly peasants will digest information more easily if it is written, for example, in a speech bubble coming out of the mouth of an imaginary squirrel pedestrian in yellow loon pants.

Yes, baby-boomers, there was no Tufty. The road safety rodent was as unreal as Iain Duncan Smith’s Sarah and Zac, if less cuddly. And perhaps the Green Cross Man’s catchphrase – “Remember, I won’t be there when you cross the road because I am a fictional character designed as a vehicle for public safety information” – should have alerted the children of the 70s to the nonexistence of their favourite traffic-awareness superhero.

As an adopted child, my acceptance of my situation was greatly eased by early exposure to a book called Mr Fairweather and His Family. It was the beautifully illustrated story of a man, Mr Fairweather, who, having failed to find the emotional satisfaction he craved from getting either a cat, a dog or a wife, finally achieved it by getting an abandoned child off an old woman in a room full of cots in a grey government building.

Alcohol or drugs would doubtless have provided Mr Fairweather with similar consolations to fatherhood and would have been cheaper than a child in the long run. Nonetheless, the utilitarian fiction of Mr Fairweather and His Family was a superb piece of socially useful work I treasure to this day and I remain eternally grateful to its titular and nonexistent, ennui-ridden antihero Mr Fairweather, the Josef K of prescriptive childcare literature, for normalising my early years.

But not all fictionalised information-carrying characters are as popular as Tufty, the Green Cross Man and our jaded Mr Fairweather, with his disappointing cat, his unfulfilling dog and his unstimulating wife. People with long memories, who perhaps visited western Canada in the 80s, may nonetheless struggle to recall the once widely reviled public infotainer, Chilliwack the Aids Ptarmigan.

A plump cartoon gamebird in a Vancouver Canucks ice hockey shirt, voiced by the legendary Canadian comedian Richard Lett, it was Chilliwack the Aids Ptarmigan’s duty to instruct the gay communities of Alberta and British Columbia about safe-sex practices during the first Aids panic.

Over music provided by Ontario progressive rockers Christmas, a series of crudely drawn information films pictured stereotyped Tom of Finland-type lumberjacks about to get down to business in Rocky Mountain log cabins, only to find the Aids Ptarmigan fluttering around their heads advising them to act responsibly, squawking his catchphrase: “We see thee rise!”

Needless to say, Chilliwack the Aids Ptarmigan swiftly became the butt of a thousand Canadian standup comedy routines and his short-lived, sex-fearing reign of gay terror has been largely erased from cyberspace by censorious and retrospectively ashamed Canadian public health bodies.

Given the long history of unconvincing public information avatars, initially I wondered why it was that Iain Duncan Smith’s Zac and Sarah had annoyed everyone so. Andy Burnham went as far as to say the DWP had been caught “red handed”, even as he and his Labour moderate co-candidates themselves assume the blurred penumbrae of implausible forgotten fictions.

Zac and Sarah may not be real, but perhaps they are not entirely unreal. I looked closely at their pictures in Iain Duncan Smith’s false pamphlet. The pair looked as convincing as anyone. A woman I might have met at a library once. A man I might have kicked a ball around with in a south London park. And yet they were products of a propaganda machine.

I looked at Iain Duncan Smith on a YouTube interview clip. His skin covered his body accurately. Hair grew convincingly out of parts of his head and from patches on his arms. Teeth protruded from his gums. His ears were on the side of his face and his mouth opened and closed when he spoke. Was it, perhaps, all too good to be true?

The right has a colourful recent history of fictitious personalities. Former Conservative party chairman Grant Shapps was briefly thought to have been the unreal alter ego of a pseudonymous internet privateer called Michael Green, and some even suggested the actual Shapps had been substituted by an alien clone after a UFO abduction in Kansas in 1989.

The left has interrogated itself about its election failure, but maybe the battle was lost some time ago? This Zac and Sarah, the unreal people, selling a political fiction, maybe they are just the tip of the ice cube? Maybe it’s all unreal, all the way down, the speeches, the photo opportunities? Actors move across a canvas. Paint splashes on a stage. Non-negotiable promises come and go.

I am in Edinburgh at the fringe festival. I walk to my venue, across town, at around midday. And every day, at the same time, I find myself moving east down the cobbles of the Royal Mile, against the upward flow of human traffic, in a vast throng of people. Actors press towards me, in animal masks and historical costumes, offering me leaflets and imploring me. How much easier it would be to turn away from my intended destination and move in their direction, flowing with them, like driftwood carried by a flood.

Stewart Lee’s A Room With a Stew is at the Assembly Rooms, Edinburgh, until Sunday and in London from 21 September