On a sunny Thursday afternoon, the Covent Garden branch of Gong cha is doing a roaring trade. Staff behind the counter are busy preparing drinks for a string of customers, all ordering from an electronic pad in the corner. One leaves with a purple concoction flavoured with the root vegetable taro; another sips on a milky tea laced with brown sugar “pearls”. A third grabs a bright drink tasting of passion fruit and adorned with floating coconut jelly.

It’s a scene being played out more and more as bubble tea shops like Gong cha pop up around the UK. Wisbech, Cambridgeshire, has just got its first (called Just Poppin); in Canterbury, Kent, there are six shops to choose from; and a new branch of American bubble tea brand CoCo recently had dozens of people queueing down Glasgow’s Bath Street.

Alongside the specialists, high-street stalwarts are also turning their attention to the drink. After dipping its toe in the water last year, Costa Coffee has put three bubble tea frappés on its summer menu (in addition to the two more-conventional versions it sells under “iced teas”), while supermarkets have added DIY kits to their shelves. After decades of bubbling under the surface, this intriguing drink appears to be getting its time in the spotlight.

The exact origin of bubble tea (or boba tea, as it’s also commonly known) is disputed – but all of the stories take us back to Taiwan, and usually to the 1980s. It’s widely agreed that the first iteration was a shaken iced tea with an added fruit flavouring, and that it was named after the froth that floated on the top. At some point, someone had the bright idea of adding round pearls of tapioca (a starch that comes from the roots of the cassava plant and was already popular in desserts) to the mix. Typically sinking to the bottom, these are the “boba” of boba tea – the word means “balls” in Cantonese.

It may seem extraordinary to anyone who can remember being dished up tapioca pudding – AKA frogspawn – at school, but the combination of refreshing milky tea, sugar and these slightly chewy little orbs proved a hit. Taiwan’s consumers embraced the drink and there are tens of thousands of boba outlets in the country today. China boasts hundreds of thousands, and the drink has made millionaires (even billionaires) out of some of the big chains’ founders.

“It took a while for it to go to the western world,” says Assad Khan, the CEO of UK brand Bubbleology. “It started in some of the major Chinatowns in big cities.” After tasting the drink in New York, Assad launched his first shop in Soho, London, in 2011 – a stone’s throw from the capital’s Chinatown.

Bubbleology now has 42 outlets, 33 of them in the UK. Alongside it, other new independent names have also set up shop, as have retailers from Taiwan and China.

One reason for the growth, says Paul Reynish, global CEO at Gong cha, is that “there’s a reasonably low barrier to entry. You don’t need much to run a bubble tea shop, although that depends on your quality credentials.”

His chain, which he says prides itself on its use of a good, “single garden” tea as a base for its drinks, originated in Taiwan in 1996 and now has more than 2,100 branches around the world. In the UK, it has new or imminently opening branches in Bristol and Norwich and, later in the year, a Belfast outlet will follow. “Most of the growth has come in the last five years,” Reynish says. “It’s going gangbusters.”

“Early adopters are Asian because they have grown up with it, but very quickly they bring their friends and that cohort is quite diverse,” Reynish says. The drinks are most popular among young female consumers. “Young girls seem to be the real growth in the market – 10- to 20-year-olds,” says Tim Lai, whose family runs Taipec, a company supplying bubble tea shops around the UK.

Their interest has been driven by who they have seen drinking it – stars of K-pop and social media – says Zoia Tarasova, a behavioural analyst at consumer insights agency Canvas8. “Many of these celebrities and social media influencers endorse bubble tea on popular platforms such as TikTok,” she says. Young people also have a “general openness to tasting diverse new food and drink flavours inspired by foreign cultural traditions.

“Once favoured exclusively by east Asian diaspora communities in the US and the UK, this tea is also establishing itself as a new favourite with young people with no personal connection to this region,” she adds.

In fact, young people with a connection to the place where bubble tea was born may not recognise some of the drinks that pass for it in the UK. Alongside the traditional tapioca infused with brown sugar, you can now often select toppings such as fruit tapioca, jelly pieces flavoured like coconut or fruits, custard or grass jellies, or popping boba filled with fruit juice or syrup.

Bubbleology’s menu, Khan explains, has been customised to cater for the UK market. “In Asia you will find most bubble tea stores are heavily dominated by milk tea with tapioca,” he says. “We sell more popping boba than we do tapioca.”

Lai, whose parents came from Taiwan, says popping bubbles are his company’s bestseller too. “If you were to show that to Taiwanese people they’d think we’d mutilated bubble tea,” he says.

When I visit the Covent Garden Gong cha, Vidam, 21, and a friend are buying drinks. He says he first had bubble tea seven years ago and didn’t like it much, but tried it again about three years ago and has now become a fan. He even has a store loyalty card.

His friend, who does not want to be named, is from Malaysia and says she had her first bubble tea as a child. “It’s a big part of the culture where I grew up. I tried it when I was really young. I don’t remember life without bubble tea.”

Today, however, she is having an iced tea, because the bubble tea on offer here is too sweet. “I think it’s a little worse than in Malaysia. People here prefer sweeter flavours.” Vidam suggests that “the quality of the pearls is different, too”.

Sweetness really is a point of difference in the UK. Costa’s blueberry burst bubble tea, for instance, has 119 calories in a 408ml serving, and a sizeable 26g of sugar – that’s more than in its lemonade or standard serving of hot chocolate.

When I ask Lai about his favourite bubble tea, he says he doesn’t often drink it “because it’s so sugary”. But Reynish says that it doesn’t have to be high in sugar, as most of his shops offer the choice to reduce the sweetness of the drink – at Gong cha you can opt for different levels, including 0%.

The customisable nature of bubble tea is a big part of its appeal, says Lai. “If a group of 10 friends go into a bubble tea shop they can all have something different. They can go back five times and across 10 friends not have the same drink twice.”

Sugar aside, the teas also tend towards ethically unsound disposable packaging, with many shops putting a plastic seal over the top before shaking the drink. But Assad says Bubbleology will launch reusable cups in the summer (and incentivise customers to use one), and some brands have introduced paper tops. Most are transporting ingredients from Taiwan, though, which raises its own questions regarding carbon emissions.

These drinks are not cheap, either. While the £5 flat white only recently hove into view, bubble teas have been hovering around that mark for some time.

But that does not seem to be putting customers off. Analysts suggest that the bubble tea market was worth $2.46bn last year and will near $5bn by 2032. That’s still a tiny fraction of the global coffee market, but heavily suggests that many, many more people will soon discover the joy of tapioca-adorned drinks.

Khan believes this to be true. He says it’s an impulse purchase, but compared with other impulse buys it is still relatively unknown to much of the public. “If I was to say to someone, ‘Have you tried ice-cream?’ they will say, ‘Yes.’ If I say to someone, ‘Have you tried doughnuts?’ they will say, ‘Yes.’ If I asked about bubble tea, I would guarantee the majority of people would say, ‘No.’ Until we get to that point [where they say, ‘Yes’] it’s not a mature market.”

He believes bubble tea could follow a similar trajectory in the UK to sushi. “We are very early in the growth cycle,” he says. Starbucks has just launched three bubble tea drinks in North America but says it so far has no plans to do so in the UK. McDonald’s offers it in Hong Kong, but not elsewhere. Reynish at Gong cha says the chain is “underpenetrated in the UK”.

There are plans to change that. Last summer, Bubbleology launched make-at-home bubble tea kits, which are now on sale at retailers including Morrisons, Tesco and Asda. Assad likes to imagine these kits sitting in UK cupboards alongside more traditional tea and coffee. Elsewhere, John Lewis recently added a bubble tea kit to its gift range.

Tan Heng Hong, a senior food and drink analyst at global market research agency Mintel, says Europe and North America now account for 41% of launches in the ready-to-drink, boba-based tea market.

“We expect the next growth phase for boba in western markets will be in dairy and ice-cream,” he says. “In Malaysia, for example, Nestlé launched a boba brown sugar ice-cream that combines chewy boba and indulgent brown sugar sauce.”

Jane Wynn and her eight-year-old daughter Rose, from Ystrad Mynach in south Wales, fell in love with bubble tea in 2022 when they visited a shop in Cardiff. “After Covid, it was nice to just go out and do something different,” she says. “I used to work with a colleague from Thailand who joked she lived on noodles and bubble tea, so when we saw a shop we went and tried it.”

There are now at least bubble tea six shops in Cardiff (including a branch of Bubbleology), but Jane says their favourite outlet is Honey Dots in Bargoed, a town four miles north of Ystrad Mynach. Rose says that she and her older brother Carter, 13, “love how the boba pearls pop. My favourite is probably passion fruit and strawberry pearls.” Jane explains that while her children also like the coconut jelly, she finds it “a slightly odd texture” and tends to go for the traditional brown sugar teas. “It’s nice that you can customise them,” she says. They opt for 50% of the standard sweetness although, she adds, “I’m sure that’s probably about 50 teaspoons of sugar.” They’ll have it instead of a dessert if they’re out, or as a treat. “The only thing for us is that they are so expensive,” she says. “If the three of us go out for one it’s easily £20.”

After we speak, Jane gets in touch with some big news: a new bubble tea shop is opening in their own little town. The boba bubble, it seems, isn’t bursting any time soon.

• This article was amended on 22 May 2024. An earlier version misspelled the name of the Mintel analyst Tan Heng Hong.