Most people come back from a holiday in the Caribbean with a tan, a souvenir string hammock that will never be used, and a bottle of rum cradled between the dirty clothes in their suitcase.

George Frost turned his summer holidays in Barbados and Jamaica into 200,000 bottles of rum — not for personal consumption, luckily, but that’s the number sold by his boozy start-up, The Duppy Share.

The youngest son of the late broadcaster Sir David Frost won’t admit how young he was when he first took a sip of Caribbean rum — except to say that it was well before he’d have been allowed it and that he’s always loved it.

It was just something to drink, for a while, though, as Frost went straight from uni to a job at posh concierge business Quintessentially.

He “bumped into [its founder and Camilla Parker Bowles’ nephew] Ben Elliot via a friend of friend in Spain; he offered me a job as a glorified receptionist of its members’ club in Soho”.

Frost worked his way up, and became head of new business at Quintessentially, “but then I had my eureka moment of setting up a rum brand”.

It was 2013 and he was at the Notting Hill Carnival for a 17th consecutive year “when I realised that there wasn’t a fun young Caribbean rum. A few rum punches later, I decided, ‘there’s an opportunity here’.”

The name came from a rum night at an east London pub. “A guy was explaining the concept of the angels’ share, that some Scotch whisky evaporates off to the angels. I asked, ‘what’s this called in the world of rum?’ and his answer was, ‘the duppy share’ — in the Caribbean they believe that mischievous duppies [spirits or ghosts] swoop between distilleries, stealing the best of the rum. I said, ‘that’s the name’.”

Was the next step a glamorous Caribbean rum-supping holiday? “I wish!” Frost laughs. “Alas I knew the rums so well that I didn’t need to.” Instead, he linked with a former marketing boss of spirits distillery William Grant and Sons, who connected Frost to Duppy’s bottlers, labellers, and the blend maestro who mixed a five-year-old “smooth, oaky, buttery” Bajan rum with a “feisty, powerful” three-year-old Jamaican rum. It’s bottled in what Frost jokes is “the UK’s Caribbean — Doncaster”.

The Duppy Share hit shop shelves swiftly “because of something that really embarrassed me at the time”, Frost admits. “I was ‘stalking’ [rum expert] Ian Burrell, and he was speaking at a Selfridges rum evening. I butted my way to the front, like a kid desperate to see David Beckham, and rudely interrupted his conversation to talk about The Duppy Share.

“About 10 minutes into the conversation I realised both that my verbal diarrhoea had blocked him from saying anything, and I’d ignored the lady he’d initially been talking to. So I asked her, ‘what do you do?’ She responded that she was Selfridges’ spirits buyer.”

A follow-up meeting went well, and Frost got his Selfridges listing. “From then on, bars and retailers would say, ‘well, if Selfridges has got it, I’ll take it’,” says the entrepreneur, who is 32 and lives in Ladbroke Grove.

He dismissed the expense of a big launch event, but used Instagram and celebrity tie-ups (including making a birthday cocktail, Dark and Stormzy, for rapper Stormzy’s party) and wooed bartenders.

In its first summer, The Duppy Share became the best-selling rum brand at the Young & Co’s Geronimo Inns gastropubs chain, “beating Captain Morgan and Havana Club, which showed it wasn’t just me who liked The Duppy Share”. It was then listed in Sainsbury’s. “that was probably our breakthrough moment,” Frost reckons.

The Duppy Share is stocked in 4500 shops, including Harvey Nichols, and John Lewis. Frost has raised £1.2 million, “from friends, family and fools”, he says wryly.

Backers include Ian Wright — “his parents are from Jamaica, he loves the rum” — environmentalist Ben Goldsmith, producer Fraser T Smith, and rapper Kano.

Frost has launched the Duppy Share in France, its first export market; Germany, Czech Republic and South Africa are next on the list for 2019. UK rum sales reached £1 billion for the first time last year; Frost flags the fact that The Duppy Share has outsold Sipsmith gin by 25% in like-for-like sales in both the brands’ first three years.

Still, he’s adamant that his rum business “isn’t a success yet — but hopefully we’ll make it”.

And if it does? “Then maybe I’ll be able to afford to go on a couple of nice Caribbean trips to celebrate. But not till I deserve it.”

The Duppy Share

Founded: 2015

Staff: 4

Turnover: £1.1 million forecast for 2019

Business idol: Ben Elliot, founder of Quintessentially. “My first boss — he works as hard today as he did on his first day.”

Best moment: “Any time that I see The Duppy Share in the hands of people who love rum.”

Worst: Packing 15,000 gift packs for Sainsbury’s: “come bottle 14,576, our fingers were decimated with deep cuts and gashes.”