Welcome to the billionaires’ new piggy bank. A bank vault in a grade-II listed 120-year-old former mansion next to the Dorchester Hotel on London’s Park Lane will open for business next week.

This is no ordinary bank. This one will be slightly more discerning of its customers than the average high street bank branch. “We won’t deal with millionaires,” says Sean Hoey, managing director of the facility, run by International Bank Vaults (IBV). “We will be dealing only with billionaires.”

Hoey, who was poached by IBV from Harrods where he was in charge of the Knightsbridge department store’s safety deposit boxes, claimed the new site would be “far more exclusive than Harrods”.

Facebook Twitter Pinterest Inside the IBV safe room. Photograph: PR handout

It will definitely cost more, and that is a core part of the sales pitch. “We are the most expensive safety deposit box in London; actually, in the world,” Hoey says. “But you know the saying, ‘You get what you pay for,’ and the customers here will be king.”

The cheapest safety deposit box, which is just 5cm high, 16cm wide and 49cm deep, costs £600-a-year-to rent. That compares to £465 for a box twice the size in Harrods, and £240 in Metro Bank – the UK’s largest supplier of safety deposit boxes with 150,000 boxes across 70 branches.

The smallest box is still big enough, Hoey says, to store a wide range of jewellery and “a fair few gold bars – they’re only the size of your mobile phone.” If billionaires have more gold than that there are boxes the size of filing cabinets, and even a whole room for £2.5m a year. “We have had a few enquiries about it.”

IBV, which is owned by South African multimillionaire Ashok Sewnarain, said it was opening the London vault due to spiking demand from the world’s wealthiest people for safety deposit boxes, in fear of a possible reaction against rising inequality. Hoey says the wealthy also fear the possible impact of the climate crisis, and are increasingly storing their wealth in gold bars as banks begin to charge them to store cash deposits.

Facebook Twitter Pinterest The grade-II listed 120-year-old former gothic mansion next to the Dorchester Hotel on London’s Park Lane. Photograph: PR handout

He says the bank vault, which is in Stanhope House – a gothic-style mansion built in 1899 for soap magnate Robert William Hudson – will have more of the feel of an “exclusive private members club than a bank”.

Sewnarain has bought a Rolls-Royce with the number plate II IBV, which can be booked to ferry customers to and from the vault. IBV’s advert for a chauffeur to drive the Rolls states: “Our clientele is the UHNW [ultra-high net worth]. IBV London requires the experience and professionalism of a well-trained chauffeur to welcome and drive our high-profile/esteemed clientele to their desired destination.”

When they arrive at the site, customers will be greeted by two doormen who will guide them through the security which includes fingerprint and iris scans to open doors to the basement vault. Then, “white-gloved custodians” will help customers collect their boxes.

Facebook Twitter Pinterest IBV’s Rolls-Royce chauffer service. Photograph: PR handout

The vault is protected by steel-lined walls, ceiling and floor to prevent robbers from tunnelling underneath. IBV also has three branches in South Africa, as well as vaults in Zurich and Dubai.

Hoey says he has no idea what people store in their boxes, and discretion and privacy is the appeal of holding boxes. But from his experience at Harrods, where he worked for more than 30 years, he says the main items are jewellery, watch collections, gold bars and coins, documents, art works and family photos.

“At Harrods we had women who would come in the afternoon to collect their jewellery, go to the function in the evening … and then come back in the morning to return a diamond necklace or whatever.”

Anyone can apply for a box – if they have enough money – but Hoey says all applicants will be vetted to ensure “we maintain a certain calibre of clients”.

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“We don’t want money-launderers or undesirables, we want to know our customers. Most will be referred to us by private banks, but we will still vet them again.”

He says some of the people who had already applied would be rejected because the bank’s committee had doubts about the origins of their funds.

Many prospective customers, Hoey says, are rich people from overseas (mostly Russia, China and the Middle East) who maintain a home in London in the summer. “They want to know that when they go home, all of their valuables are safely stored in central London.”