One lunchtime, a few weeks into the first lockdown of 2020, a customer came into Caliendo’s Gelato in London’s Kentish Town, bubbling with excitement. “I asked her how long she’d been waiting,” says Michelina Caliendo-Sear who, with her partner, Fiona Bell, had opened the ice-cream parlour in December of 2019. “She said over half an hour. I went to the back door and looked out.” Customers were queueing right round the corner and far up the sidestreet. They were clearly prepared to wait a very long time indeed for scoops of blackcurrant and liquorice or fig and walnut and, most of all, for the famed Bronte pistachio, made with prestige nuts harvested from the very foothills of Mount Etna. “We were their treat at the end of their lockdown walk. That was when I knew the business was going to be OK,” Caliendo-Sear says.

In May, Caliendo’s was named the first ice-cream parlour of the year, in a competition run by the Ice Cream Alliance, which represents hundreds of parlours and producers. “We are honoured and proud to have won,” Caliendo-Sear says, “especially among such stiff competition.” She’s not wrong. The fact is that ice-cream – a broad term that can cover everything from hard scoop to gelato, soft serve to kulfi, dondurma to sorbet, frozen yoghurt and so much more – is having a moment. You could say that right now, ice-cream is hot. In 2022, the value of the UK sector rose by 6% to £1.7bn. While tough trading conditions recently have taken their toll, before the pandemic the number of dedicated ice-cream parlours was rising by 20% a year. Nearly two-thirds of all ice-cream manufacturers operating today have been incorporated only since 2015.

Katy Alston, president of the Ice Cream Alliance, believes its surging popularity is directly born of Covid trauma. “After everything we’ve been through,” she says, “we’re all looking at what’s really important to us, rather than what we think should be important. I can watch everyone from two-year-olds to 100-year-olds fall silent with one of my ice-creams in their hand.” Alston, a former nurse who lives in Bognor Regis, got into the business 20 years ago when her partner bought her a vintage ice-cream van. They renovated it and took it out to weddings and corporate events to dish out soft-serve cones. But the ice-cream van business is in decline. In the 1950s there were about 20,000. Now it has stabilised at about 4,000.

Instead, in 2015, Alston set up Pink’s Parlour in Bognor, offering a range including cherry delight, honeycomb and a vivid DayGlo concoction involving blue and pink candy floss, called unicorn. “I realised there were people who wanted jobs but who needed flexible hours or didn’t have the right CV.” A passion for getting people back into work, combined with a love for really good ice-cream, created a hugely successful business. “The growth now is in parlours, places which have a story and a personality,” she says.

On weekends in central London, nights out now end with young crowds descending on hip, glossy new arrivals such as the Israeli-born Anita Gelato, famed for its clean-tasting chocolate sorbet, or Milk Train with its candy floss cones, and its cups filled with soft serve, spiked with candy carrots and squares of fudge. On the high street, dessert bar brands such as Kaspa’s and Creams are booming. Both now have more than 100 branches each across the UK selling a mixture of cakes, crepes and yes, gelato. Creams has seen double-digit sales growth in the past few months and will open another 20 branches in the coming year.

“Our customer base is very much the young at heart,” says Creams chief executive Everett Fieldgate. “It’s families, young adults, Gen Z. We also attract a lot of non-drinking cultures.” It makes sense. For teens needing a place to gather independently, ice-cream parlours are a godsend. For communities and cultures that swear off alcohol, the ice-cream parlour is a third space, much as the pub is for the drinkers. Ice-cream has become the great social unifier. It’s profoundly democratic. It’s an uncomplicated pleasure, one that calls back to childhood, when contentment was more easily obtained. As Fiona Bell of Caliendo’s says: “We’re in the happiness business. No one comes to an ice-cream parlour to be miserable.”

That happiness first arrived in the UK in 1619 with the construction for James I of an ice house in Greenwich Park, an import from Italy where the production of ice-creams chilled down with a mixture of ice and salt were something of a parlour trick for the rich. Some have queried the apparent dominance in this country recently of parlours serving Italian-style gelato, based more on milk, rather than traditional hard-scoop ice-creams based on custards. In truth, it’s just a return to the Italian origins of iced desserts. According to the food historian Dr Annie Gray, by the 18th century ice-creams had become a major craze for the rich. “There were amazing recipes in the 18th century,” she says. “Herb ice-creams, flavoured with rosemary or sage, tamarind ice-creams, brown bread flavour.”

Slowly, as ice production scaled up and sugar became cheaper, it moved from being solely for the aristocracy to becoming popular among the middle classes. The boom really kicked off with an influx of refugees, fleeing chaos in Italy, in the late 19th century. It has led to the continuing dominance of the trade by old Italian families: the Morellis of Northern Ireland, the great Scottish families such as the Mancinis and the Nardinis. In Swansea there’s Joe’s, opened by Joe Cascarini in 1922 and famous for offering any flavour you want, as long as it’s vanilla. They now have five parlours in south Wales. “There’s a queue every day,” says Adrian Hughes, the latest generation of the family to run the company. “People get to the front of the queue, ask for strawberry and are baffled when told it’s only vanilla. But once they try it, they love it.” I have tried it. I can therefore report it is indeed lovely: fresh, bright and creamy.

As a kid, the chef Jacob Kenedy, of Roman restaurant Bocca di Lupo in London’s Soho, says he liked ice-cream more than most, a habit indulged at Marine Ices in Camden Town. He got his fix on family trips to Italy and later returned for a gap year, originally to learn how to make Italian cured meats. Instead, he was taken under the wing of a master gelato-maker in Bologna. It led in 2011 to the opening of his ice-cream parlour Gelupo, just opposite the restaurant. It has recently reopened after a major renovation, making necessary space for more customers.

Over a bowl of his silky hazelnut ice-cream, he explains gelato’s appeal. “It is made with milk powder, milk and a selection of sugars, so it’s lower in fat. So rather than tasting the cream you taste the ingredient.” Where hard scoop is chilled to between -16C and -18C, gelato is chilled to around -13C. That means it’s softer. I ask Kenedy to sum up the appeal of ice-cream. “It feels sinless,” he says. “Nobody is harmed by ice-cream.”

People in the business really do seem happier than most. One bright early summer’s morning I visit the Pavilion Cafe at Victoria Park in London’s Tower Hamlets. There, perched in the window, is Terri Mercieca, a star of the UK’s ice-cream world and founder of Happy Endings. Shout line: “Everybody deserves one.” Mercieca started as a pastry chef in her native Australia before moving to the UK. She staged dessert pop-ups, and developed the ice-cream sandwiches that first made her name: malted milk parfait between oat biscuits, half dipped in chocolate, or strawberry cheesecake parfait between shortbread biscuits. “It’s hard to find someone who doesn’t like ice-cream,” she says. “It’s soothing. It’s reassuring.” A couple appear at the window and ask what she’s selling. Today it’s two soft serves: a pineapple and lime, and a milk ice-cream, increasingly the focus of her business. The buyers order their cones and grin at the very first lick. “I like selling ice-cream to people,” she says. “It’s fun.”

Back at Caliendo’s Gelato in Kentish Town, trade is picking up. The business was a career change for Bell, formerly a project manager after serving in the forces, and Caliendo-Sear, a commercial pilot. She had helped make a family tree for her mother’s 80th birthday six years ago and discovered that every generation of the Caliendo family, who arrived in the UK from Napoli more than 100 years ago, had been in the gelato trade. The couple decided to keep the tradition alive, went on an ice-cream-making course, and opened the parlour, themed around the 1969 movie The Italian Job, complete with parked-up red Mini.

They offer me some of their ice-cream. I conclude it would be rude not to. I get dollops of their pomegranate with spiced apple, their apple pie with biscuit crumb, and the fig and walnut. I know I’m meant to be paying attention to the details of these beautifully made gelatos. I am meant to be a food professional. But I’m really not up to the job. Instead, with a cup of terrific ice-cream in front of me, all I can think is: “Life is very good.”

• This article was amended on 17 July 2023. The Pavilion Cafe at Victoria Park is in Tower Hamlets, not Hackney as an earlier version said.