LONDON (Reuters) - They have the mooring in St Tropez and the country house in the Cotswolds but there is one other thing that the wealthy elite cannot live without: a private banker.

It is a service they can well afford. Despite the global credit crunch, the rich are getting richer and are now worth more than £400 billion, according to the Sunday Times' annual Rich List, published last week.

But the private banking sector is no longer the reserve of the ultra-rich. At one time, these boutique financiers were largely concerned with old money: that of the landed gentry with their double-barrelled surnames.

But there is a growing influx, too, of new money: celebrities, City types who net huge bonuses, and rich foreigners — from Eastern Europe, Russia and the Middle East — coming to Britain and buying up property.

Footballers, "it" girls and entrepreneurs too busy building their businesses to handle their own money are increasingly on the books, signing up to all-inclusive money management services that come with lofty annual fee structures and unspecified tax advantages.

It follows, then, that global private banking assets under management are on the up. They are now the equivalent to the entire gross domestic product of Britain, France and Germany, or one and a half times the market capitalisation of all companies listed on the London Stock Exchange.

They hit $7.6 trillion (£3.8 trillion) this year — up 128 percent on the year, according to Euromoney's benchmark annual survey of the wealth management industry.

"While concerns grow about the state of the economy, there is no doubt that global wealth continues to increase at a rapid pace," says Clive Horwood, editor of Euromoney magazine.

"These wealthy individuals and families are spread over an increasingly diversified geographic base and are demanding a higher quality of service from companies and people who manage their wealth.

"It's no surprise, therefore, that all of the world's leading financial institutions are focusing more of their efforts on this high-growth, but extremely challenging, business opportunity."

A growing number of high street banks are getting in on the act too, on the back of the booming economy of recent years that has pushed house prices sky-high and led to a growing mass affluent sector.

Their premier banking services are aimed at those who want to receive a service akin to that enjoyed by the elite, but have nothing near the same amount of money.

Above all, these and their more traditional counterparts claim to offer a more personal service than standard current accounts.

But, other than the associated prestige, what exactly do you get? And do either offer real value for money?

Big-name global investment banks and asset managers — Credit Suisse, Schroders and Barclays Wealth among them — offer private banking services.

Traditional private banks are lesser-known among the population at large, but many have been around for eons.

C Hoare & Co was founded in 1672 by Richard Hoare at the sign of the Golden Bottle in Cheapside, London, while Coutts & Co, now the private banking arm of the Royal Bank of Scotland (RBS), has its roots in 1692, when a young Scot, John Campbell of Lundie, set up business as a goldsmith-banker at the sign of the Three Crowns in the Strand.

The earliest extant records show that not only did Campbell supply plate and jewellery; he also offered a comprehensive banking service, discounting bills, making loans and taking deposits.

Many of his customers were his fellow countrymen, including his clan chief, the Duke of Argyll.

Campbell enjoyed royal patronage when Queen Anne commissioned him to make the collars and badges for the Order of the Thistle.

And today Coutts — a name that first appeared in the title of the bank in 1755 when Scottish banker James Coutts was taken into partnership — is famed for looking after the money of members of the Royal Family.

The heritage of Butterfield Private Bank, meanwhile, stretches back to 1858, when a merchant trading firm founded by entrepreneur Nathaniel T Butterfield became the Bank of NT Butterfield & Son.

Its London-based private banking arm was incorporated under previous ownership in 1979 and became a wholly-owned subsidiary of Bermuda-based NT Butterfield & Son in 2001.

It has six other offices around the globe, unsurprisingly in tax havens and places associated with the uber-rich: the Bahamas, Barbados, Bermuda, the Cayman Islands, Guernsey and Switzerland.

In the Caribbean and Bermuda its doors are open to all — from the man who runs the beach bar to rich and famous residents.

In Britain, though, only the elite need apply for its top-end services: clients of its "family" division have five million-pounds plus, but it aims to attract those with wealth of double that or more.

For its entrepreneur services, it has an unwritten entry level of one million pounds of investable assets, but will entertain the idea of taking on those with £250,000 to invest in cases where there is "potential".

Services offered are holistic — everything from day-to-day banking and investment management to complex tax affairs and arranging credit for a new yacht.

"There's quite a bit of conducting the orchestra," says Butterfield director Raymond Sykes. "It's quite bizarre: one minute you can be arranging some complex loan facility or setting up trusts for the wayward kids, and the next minute you can be sending a cheque book out to a client."

Particularly at the higher end, the client is king: their wish is the private banker's command, and some of the services offered are more akin to those of a concierge or butler.

"For some clients, we run their charities," says Sykes. "Then we have clients where we will get the Bentley down to Geneva.

"And we'll make sure flowers are on old Jimmy's grave once a year because he was a faithful retainer."

This type of thing, he says, is a bit of a throw-back from the bygone era of private banking. But, if anything, private banks are doing more of it as clients become more cash rich, time poor.

"We're not quite getting theatre tickets or booking flights to Hong Kong, but (with) anything a bit more usual and the client has nowhere else to go and can't be bothered doing it themselves, they'll ask the bank," says Sykes.

All this comes at a cost. Most products are tailor-made and rates are negotiable dependant on the complexity of work undertaken, as well as clients' wealth and connections.

Full-time management of an entire family's wealth could cost up to £30,000 per year, says Andrew Jackson, fellow Butterfield director and head of its product expert group.

At the other end of the spectrum, day-to-day banking is free, but clients pay for extra services.

Increasingly, people with less impressive bank balances are able to buy into the idea of banking for the elite through a growing number of premium financial services.

There are almost half a million British households with a joint income of more than £100,000, and 2.7 million people with more than that in liquid assets to invest.

For little or no fee, consumers are able to side-step overseas call centres and hanging on hold for someone to answer their call. Instead, they can tap into a priority customer service with their own account manager.

Whether such accounts are little more than a high street bank account with a gold-edged cheque book is open for debate, though many do come with added perks.

HSBC's premier service in the UK also has an entry level of £75,000, or £50,000 of savings and investments. Those with a mortgage of £250,000 or more with the bank also qualify for the account, which give customers access to exclusive lounges in upmarket "premier" branches.