Jings, these actors look familiar. Eleven of them, conga-lining their way across the floor of a theatre  studio in Glasgow, not yet in costume, but imagine them in silhouette; imagine them in pen and ink. The little woman at the back, holding the teddy, is in her mid-fifties and not quite five feet tall. The young man at the front, Gable-moustached, is almost seven feet and has a bodyshape which only the Scots word “lanky” can fully express. Welcome to rehearsals for The Broons.

“It’s a miracle that it has taken 80 years to do this, because it’s so much a part of Scottish culture,” says Rob Drummond, the playwright bringing the comic strip from page to stage. The Broons has run weekly in DC Thomson’s Sunday Post since 1936 and the strips collected in a biennial volume, known as the Broons book, a staple Christmas gift for generations of Scottish children.

Set in the fictional town of Auchentogle (Oor Wullie, the other iconic Post strip, takes place in neighbouring Auchenshoogle) it relates the misadventures of a family living in a tenement flat at 10 Glebe Street. There’s Hen, the lanky son, butt of many a joke. There’s The Bairn, wise beyond her four years. There’s Maggie, Daphne, Joe, The Twins, Paw, Granpaw and Horace. And presiding over them all: Maw Broon, matriarch and maker of mince, the fiercely loving heart and soul. “Scotland’s happy family that makes every family happy”, as the eternal tagline has it, is a fixed point in a world in flux. Even in that very first strip, as the Post’s front page fretted over Hitler’s march into the Rhineland, The Broons was full of consoling fun and mischief. They’ve been at it since.

Written in Scots – “ken” for know, “bide” for stay, and so on – a typical Broons episode is based around some comic misapprehension. Paw, sitting at a window, gets seeds from raspberry jam stuck in his falsers, and the woman across the street is raging because she thinks he’s pulling faces. Doesn’t sound like much written down, but the magic is in the familiar charm of the black and white drawings and similarly unnuanced values – loyalty, decency, affection, amused self-awareness – for which Drummond has coined the word “Broonsian”. If a scene or line felt Broonsian, it went in the play; if not, it got the heave. This makes sense. Broons readers can be unsmiling guardians of orthodoxy. In the 1990s, The Broons experimented with colour. “A disaster,” recalls Morris Heggie, the strip’s present writer. “It stopped just short of us getting death threats.”

Heggie, 65, was hired in 1969 by RD Low, the managing editor who had invented The Broons. He works closely with 72 year old Peter Davidson, who, since 1994, has been on his second stint of drawing the strip. There have been just five artists in 80 years. Davidson, too, has a connection to the birth of The Broons. As a child in Dundee, he was friends with the son of Dudley D Watkins, the “genius” – oft described – who drew the strip from 1936 until his death at his drawing board in 1969. Davidson saw Watkins at work many times, memories scented with Indian ink, and was even invited to use his pens. This was a passing of the torch. He and Heggie are tradition-bearers. “Last of the Mohicans,” is how Davidson puts it.

Even though the Post now sells around 150,000 copies a week, down from 1.6 million in 1970s and early 80s, they are proud to uphold its verities. These are men who grew up in the Scotland the strip still portrays – one in which boys know how to guddle fish – and are keen on the idea that The Broons exists in two different time zones at once, the present day and a sort of perpetual 1950s. The characters have mobile phones, but they also have two old tin cans connected by string. Heggie writes at home, feeling like Granpaw Broon, surrounded by six grandchildren. The stories just come to him. He knows to avoid politics. Nicola Sturgeon has appeared in the strip, but only as a public figure. You’ll look in vain for mention of the Scottish independence referendum, and whether Maw and Paw voted to leave the EU (Brooxit?) is a thing unknown.

Rob Drummond, by contrast, sees those issues – and the fact of a Conservative government that Scots did not elect – as context for the show. “In Scotland, our values are very different from those in England. We’ve established that with the way we vote,” he says. “There’s something in The Broons about being a family, a tight-knit community that looks after each other, that’s almost a socialist message. The weakest members of us, the Daphnes and Hens, are always alright at the end of the day … Without wanting to make too much of that in the script, there is an element of why we should be proud of the way we’re going in Scotland.”

This makes the play sound more earnest than it will be. It’s very much a comedy, but with more emotional heft than the strips, plenty of sing-alongs, and is based around Maggie’s approaching wedding. A quarter of the material is adapted directly from classic Broons stories. To turn ten-frame comics into two hours of theatre, Drummond looked to the perhaps unlikely figure of Quentin Tarantino for inspiration, studying Pulp Fiction for its multiple characters and crossover storylines.

The Broons were based on real people, RD Low’s family members and work colleagues, and readers continue to see their own loved ones in them. Joyce Falconer, the Aberdonian actor who plays Maw, feels that these characters are in her DNA. “I grew up with The Broons,” she says. “Me and my sisters would lie on our tummies and read them out loud. They were real to us. Maw was so familiar. She was my aunties, my nan. And The Broons and Oor Wullie were the only things written in Scots at that time. ‘They’re sayin’ words that we use!’ So that made it personal.”

How The Broons speak is a question with which cast and creatives are grappling. A dialect coach has been brought in. The question of whether one should say “square” or “Lorne” sausage has been the subject of earnest debate. There has been speculation over the years as to where Auchentogle is supposed to be. Dundee? Glasgow? Heggie and his predecessors have taken care never to provide an answer, but as soon as an accent is heard on stage, the truth will be out. Right now, the thinking is east coast rather than west, Lorne not square. Fife, maybe. Either way, the very fact that the Broons will speak and move on stage – and that the child roles will be played by adults – is as radical as Dylan going electric. The hope is that no one shouts “Judas!” from the stalls of the Ayr Gaiety.

Unlikely, perhaps. But the truth is that not everyone loves The Broons. “Scotland will be reborn the day the last minister is strangled with the last copy of the Sunday Post,” is a notorious comment by the political theorist Tom Nairn. Some see the strip’s portrayal of Scottish life as narrow, parochial and stiflingly conservative, not at all the sort of thing contemporary theatre makers should be bringing to the stage. “That sounds a wee bit ‘bah humbug’ to me,” says the director Andrew Panton. “I don’t see why you would speak like that about something that has brought a lot of people a lot of joy and survived for so many years.”

Everyone involved in the play feels the responsibility of that historic joy, the need to get it right. But even if they don’t, The Broons will endure. It’s like Shakespeare; strong and pure enough to withstand all adaptations and attempts at commercial exploitation. Maw Broon’s Cookbook was Scotland’s number one bestseller for weeks, nutritionists tutting over the calories in her clootie dumpling; there is a popular series of golden oldie albums; and one newspaper even named Maggie Broon as number one in a Top 100 of sexy Scotland (full disclosure: I edited the list). The Broons has survived all of these potential indignities, pinny unruffled, pipe still lit.

“I don’t think we’ll keep everyone happy,” says Drummond. “But at every stage of the journey we’ve been careful to do The Broons proud.”

A version of this article was published in The Guardian