Take a look inside London's underground Fort Knox - where the wealthy go to store their valuables

With that in mind, London developer Amazon Property (no relation to the online retailer) opened the £30-million Armitage Vaults 40 feet below the city's West End.

The vaults have 10,000 square feet of storage space encased in one metre thick ferrous-concrete, and insurance to cover items worth up to £10 million.

Both businesses and private clients have signed up to use the facilities.

Tom Archer, operations Director of Amazon Property said: "The facility is new, however we have already had significant interest and the vaults are already 20% let, with 75% of users being from the UK, the remainder are international. Around 50% of the tenants are wealthy private clients, the balance are businesses."

Take a look inside.