Once upon a time baking was something your Granny did, turning out fluffy pancakes and scones on to a wire tray in her wee kitchen with the back door open. These days it’s a big glamorous business, an aspirational lifestyle choice set to a backdrop that resembles an explosion in a Cath Kidston shop.

As we all know, that's largely thanks to a certain TV programme that has now become a global cultural phenomenon: The Great British Bake Off. The one-hour show charting the highs and lows of extreme cakery returns this Wednesday evening for another 10 weeks featuring 12 contestants, three challenges, two comedians, endless headlines, one national treasure and a twinkly-eyed bearded Scouser with more wattage than Blackpool illuminations.

Part cooking show, part game show, part reality show, GBBO (as it’s affectionately known) has been gripping the nation since 2010 when a pleasant bespectacled young chap called Ed Kimber was crowned the show’s very first winner. It’s been making huge leaps in the ratings ever since. Last year, when everyone’s cupcake sweetheart Nadiya Hussain won, it was the most-watched show on British television, causing 15 million viewers to blub along joyfully with 81-year-old co-host Mary Berry. That’s almost three times the population of Scotland watching a show about cakes. But what does that say about us and the times we live in? And just why is the series so damn successful?

Well, in a word, it is 'safe'. It’s nice. It’s comforting. It’s friendly and inclusive - as Nadiya proved. It's easy. In world of a Brexit, Boris, Isis and Trump, it’s a retreat from the nasty realities of the world to a cosy, more innocent place where the grass is greener, the birds are singing, we’re all inside a big white tent and the biggest worry is whether Nancy from Northampton’s Victoria sponge won’t deflate as it exits the pastel-coloured oven.

And it’s all in the chemistry, or rather 'casting' as they say in TV-Land. GBBO is certainly not ageist, with one silver fox presenter in 50-year-old Paul Hollywood, all denim-blue eyes and bad-cop routine, and delightful fantasy Grandma figure Mary Berry at the grand old age of 81, all sugar-spun hair, flamboyant florals and the good cop in the relationship. Throw in a couple of sharp, funny, smart-mouths in Mel Giedroyc and Sue Perkins, and it’s a recipe for success: a handful of peachy keen contestants, a good dollop of nostalgia, a teaspoon of Dunkirk spirit, a large pinch of Carry On-style innuendo et voila: The Great British Bake Off.

It’s the kind of programme the late Victoria Wood would have made mincemeat of in a merciless sketch, had she not been so busy winning the Comic Relief celebrity Bake Off two years ago. Now Sex and the City star Kim Cattrall has signed up for the next one in 2017. Which is appropriate given the way the hit US comedy fetishised the humble cupcake every bit as much as it did Manolo Blahniks. Everyone’s at this baking mullarkey.

Jacqui McKechnie, senior lecturer in psychology at Glasgow Caledonian University agrees, believing GBBO’s success is due variously to escapism, accessibility and its aspirational nature. “The news is pretty bleak these days and GBBO is shot in summer and broadcast throughout the autumn filling our screens with sunshine and lifting the spirits. Also it’s not like other talent-type shows on TV, because not everyone can sing, or dance or survive in the wild, but pretty much everyone can go in the kitchen, switch on the oven and have a go at making a cake. And it’s properly aspirational, not in terms of having things, but in terms of achieving things. It’s inspiring. People watch the contestants on GBBO and think, I could do that.”

Though not a fan, investigative food journalist and Sunday Herald food critic Joanna Blythman (see box out, right) believes its appeal lies in the reaction to the world around us. “Right now people are anxious and depressed about the constant diet of frightening news. In the Great Depression of the 1930s, people flocked to musicals to feel good, and GBBO works on a similar level. It’s a comfort blanket: regimented, undemanding and you know exactly what’s going to happen. You are guaranteed a heartwarming show with a bit of jeopardy thrown in. It’s a formula that works for a lot of people.”

Undoubtedly, GBBO is a carefully crafted show that places great emphasis on the casting, assembling just the right mix of gender, ethnicity and class –although this year’s bunch are undeniably and solidly middle-class, from young Northern Irish aerospace engineer Andrew and Yeovil headteacher Val, to Rav, a student support officer from Kent and Benjamina, a teaching assistant from London.

Broadcaster and cultural commentator Stuart Cosgrove thinks it is a near-perfect format that requires little of the viewer but to be entertained. One of its magic ingredients is simplicity. “Basically, it’s a knockout format, easy to understand, with viewers under no obligation to learn any complex rules – unlike The Voice for example where sometimes you have no clue what’s going on.”

It also manages cleverly to sum up the popular notion of the British character in just 12 contestants. “Of course the BBC is under moral and political pressure to create a diverse selection of contestants that reflects our society,” explains Cosgrove, “but GBBO also seeks out the characters we all love to watch: the dithery one, the shy one, the bombastic one, the overly fussy one, the charming one, and so on.

“The only thing that grates is its need to plaster the Union Jack bunting all over it. I don’t want to feel like I am part of some effort to cohere the nation around the Union Jack. It’s all a bit Empire, a bit overly patriotic in a place that doesn’t need it. It’s about individuals competing against each other. Why is nationhood even an issue?”

The answer may lie in the programme’s need to identify itself strongly as quirky, charming, good-sport, old-school Blighty for the benefit of foreign viewers who like to pigeonhole Brits as much as Brits like to pigeonhole other nations. Shot in the grounds of Wellford Park, a stately home in Berkshire, the show is filmed in a county-show style marquee, festooned with red, white and blue bunting and a colour palette of vintage-hue pastels. It is clearly riding the whole cosy craft wave where crochet circles, sewing bees and women’s institute skills such as jam-making and pickling are experiencing a bit of a renaissance. Sometimes it can feel a bit like twee overload, but in the main, the Great British public seems to love it.

“I find it very civilised,” says 51-year-old Bake Off fan Michelle Stewart of Glasgow. “In a world of nasty, humiliating shows like Big Brother and X Factor, it’s good to see people being nice to each other. I like the camaraderie of the presenters where Mel and Sue take the mickey out of Paul and Mary, and indulge in a bit of smutty innuendo. But most of all I am constantly amazed at the talent on show, the technical skill and the pure creativity of some of the bakers.

“I remember one guy who made a cake shaped like a windmill that had a little bucket going round on a wheel into a pond of chocolate. I thought, how did he even come up with that?”

And of course there is GBBO’s capacity to bring people together in the pursuit of excellent cakes. From the live tweeters to those who text friends while it’s on air and then phone to discuss afterwards, GBBO is probably the biggest watercooler subject in the history of British television. But it’s also a show that people can watch with their children and grandchildren – good old-fashioned family viewing at its best. Tapping into this sense of nostalgia is a powerful trigger for those who want to replicate happy experiences they had in their own childhoods, when they were forming relationships not just with parents and grandparents, but also with food.

Shirley Spear, Sunday Herald chef, founder of the Three Chimneys restaurant and chair of the Scottish Food Commission believes the programme also encourages families to bond in the kitchen. “It’s a fantastic introduction to home cooking for children, especially with a parent or a grandparent. Children love seeing their results and watching someone eating what they’ve made.”

The programme, she believes, has also contributed to a proliferation of good coffee and cake joints across the country. “Even in the far north and the Highlands you will find plenty of places for a cup of tea and a good selection of excellent home baking. And while there’s clearly an emphasis on luxury baking and wonderful ornamentation, GBBO is still all about choosing good ingredients and baking at home.”

One of the remarkable achievements of the programme is the way it has normalised baking as a legitimate male interest. Now baking is a badge of honour, an achievement to be proud of, a talent to hone for ambitious chaps keen to impress. “I love cakes and I love baking," says 55-year-old Ayrshire businessman Marcus McLeod. “I go to my mum’s every Saturday and bake everything from a light Victoria sponge to a batch of sturdy scones. But that programme gives me palpitations. I sit there shouting at the telly, ‘You forgot the baking soda! How will it ever rise now?’”

For some it’s the shouting, for some it’s the saucy innuendo and the cross-generational flirting and for others it’s the milestone moments, like the success of last year’s winner Nadiya. While GBBO has never sought to create stars, and winners have quietly accepted the accolade and gone back to their everyday lives, the 30-year-old Bangladeshi Brit from Luton has bucked this trend in spectacular style. In the 12 months since she won, she has graced the front of myriad glossy magazines, secured book deals, appeared on chat shows, been signed up as a magazine columnist, baked the Queen’s 90th birthday cake, and now has her own show, the Chronicles of Nadiya – a star is truly born, and a star that represents the changing face of 21st-century Britain, and a positive image of young Muslim women.

That diversity, says Stuart Cosgrove, is reflected in the food and cuisines so many of us now enthusiastically embrace. “Think of all the kitchens you go into and find a range of cookery books from all over the world. I think people who are foodies like the idea of cultural diversity, they expect that of food nowadays.”

It’s a strange confection, this Great British Bake Off; it’s not metropolitan, it’s not elitist, it’s not sexist, it’s not ageist, it’s not exclusive. It’s also not of the real world, but it works and it is loved. Fifteen million people laughing, crying and stuffing themselves with cake can’t be wrong.

'Sorry, I can’t stand The Great British Bake Off'

Joanna Blythman, Sunday Herald restaurant critic, investigative food journalist and author

“What we really don’t need right now is a programme all about cakes and sugar, what we need is the Great British Veg Off, where the challenge is to come up with delicious ways to get us all eating more vegetables. The awful irony is, there has never been more obesity and type 2 diabetes in this country and the most popular thing on television is all about baking cakes.

I am not a ‘my body is a temple’ person, but this programme makes me uneasy. It indulges the idea that we should all just lose ourselves in the comfort of cakes. This formula may give people nice ideas for creative baking, but it doesn’t seem to beget healthy eating.

Aside from the health issue, I find it unbearable to watch. I’m not a fan of reality shows where you have people pitted against each other in silly competitions. I’d rather watch something educational, like Rick Stein’s Far Eastern Odyssey, or Yotam Ottolenghi’s Tour of the Mediterranean. GBBO manipulates the emotions and contestants are deliberately put in situations where they have to emote for the cameras which I find insulting. And it always trots out six or seven clichéd foodie types every series.

I also think the way the BBC contrives to create a diverse cross section of society in the contestants is simply a way of showing off to the world what a wonderful United Nations the BBC is, how diverse and inclusive. Except that this is manifestly not true across the rest of its output because it is still an institution dominated by old white men.

I realise that it’s considered heresy to speak this way about a programme that is so loved and which reveres the national treasure status of Mary Berry, but in this country if you don’t bend the knee to populism, you’re somehow out of touch. For me it’s just cultural laziness.

I’m not even sure people are being turned on to baking. If GBBO is all about getting Britain cooking again, we’ve failed. You can’t preach about obesity when your primetime programme is all about sugar. And putting avocado in your cheesecake or beetroot in your brownies is not going to cut it.

So bring on the Great British Vegetable Challenge. Get Yotam Ottolenghi in as a judge. He’s done more for the vegetable cause in Britain to date than any native of these isles. Imagine the watercooler moment at work revolving around celery instead of cupcakes.”