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.”