The shopping habits of the rich may seem a frivolous subject for study during an economic downturn. Yet the tastes of those known to market researchers as high net worth individuals affect us all. For example, a few years ago, luxuries such as hot tubs, built-in flat-screen televisions and granite kitchen work surfaces were confined only to flash playboy pads. Now these are standard in many new developments.

Today, as the international rich grow more plentiful (they have thronged to London in recent years), their tastes become more familiar and their spending habits increasingly affect our economy. So, what do they squander their millions on?

One trend that may not trickle down to the rest of us is for bespoke crystal fittings in yachts (more of which later). The No1 purchase is still property. Knight Frank, the estate agent, estimates that there were more than 50 property sales above £10 million in Central London in the three months to January this year, compared with 18 in the same period in 2007. The buying frenzy in this sector is keeping prices rising at a rate of 3 per cent while the rest of the market slumps.

The proportion of owners of American Express Centurion credit cards (you have to be invited to join - substantial private wealth a must) who intend to buy property for personal use has risen by 5 per cent since last year, according to a members' survey. And 83 per cent plan to kit out their mansions with a private library this year, and installing gyms, cinemas, pools, meditation rooms and dance floors also features high on to-do lists.

When it comes to furnishings, mass-market products are shunned. More than eight in ten of those surveyed intend to buy unique items for their homes. Nick Candy, of Candy & Candy, the best-known developer of property for the super-rich in London, attributes this to consumer fatigue: “Many of our clients have ‘been there and done that' so it is essential for us to be one step ahead,” he says. Recent examples he has overseen include “lifts that take your picture and project your face onto a chandelier as you enter a room” and “mirrors that video you with a time-delay function so you can see what you look like from behind as you spin round”.

Even billionaires buy cutlery and chopping boards - but from where? Harrods, of course, although they don't actually go there in person. According to Marc Gilmour, homewares expert at Harrods' By Appointment personal shopping service, “many of our clients don't want to be seen shopping so we bring everything to them at home. If you spend £50,000 on a table you need to see it in situ”. A common situation, he adds, is for a client to “want to furnish a new home but they have no idea what you actually need to put into a kitchen. I deal with butlers, housekeepers and chefs a lot.”

Homewares now accounts for more than a fifth of By Appointment's business, with a mixed clientele of British, European, Russian and Middle Eastern customers. The personal shopping team speak Russian and are ready to fly to Abu Dhabi at the drop of a hat.

The craze for bespoke products is culminating at Harrods next month in a new service dedicated to collectors of Lalique crystal, who can have their purchases personalised. “For example,” says Frederick Fisher, Lalique's retail director, “if you see a round chandelier you like but you have a rectangular room, we could make you a rectangular one.” Gilmour adds that clients “increasingly ask for personalised features. A lot of brands that started out as bespoke designers, then turned to off-the-shelf products, are now going back to personalisation.”

But what is the attraction of brands such as Lalique? Gilmour attributes it to good old-fashioned posing potential. “Clients buy the most expensive brands like Lalique and Louis Vuitton partly to show off. They are status symbols.” The possibility of a return on investment is also attractive. “Investment pieces are increasingly popular,” says Fisher. “Some items such as crystal shower doors can add value. One customer recently had £300,000 of Lalique fittings in his yacht, which he then sold for £7,000 more than he spent.”

The credit crunch isn't even on the radar. “Luxury products have never been more popular,” Gilmour says. “These people are keen to spend money - we just have to point them in the right direction.” And those who do worry about the economy are consoled, Fisher says, by the thought that: “It's reassuring during a recession to have something that is the best.”

Fast facts

René Lalique founded the crystal company, famous for its Art Nouveau glassware, in 1886.

Lalique is holding an exhibition of rare pieces at Harrods next month.

By Appointment: 020-7893 8000

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