This is the image many of us carry of Mayfair: a sort of property version of the Gillette advert ("the best a man can get"). The grand square miles bounded by Park Lane and Piccadilly, Oxford Street and Bond Street are a bricks-and-mortar embodiment of the wealth and tradition of privileged Englishness, where shops so expensive you need a trust fund just to walk through the door are sandwiched between huge town houses and even bigger ducal mini-palaces. Mayfair, the square on the Monopoly board most worth owning.
But there has always been another Mayfair, the diametric opposite of Peter Wetherell's image of the perfect high street. Situated in half a dozen narrow streets in the area's south-west corner is a quarter known, in a hangover from more pastoral times, as Shepherd Market. Here the goods on sale have traditionally been as specialist as anything available elsewhere in the village: rubber, water sports, discipline, all sorts of services are offered at the top of grubby stairways, the path to relief lit by strategically located red bulbs.
For years, an odd, almost symbiotic relationship existed between the hookers and pimps of Shepherd Market and the toffs and landowners in their piles on the other side of Curzon Street. Until it finally appreciated the embarrassing implications and sold out in the Sixties, Harrow School was the principal landlord of the Market - Winston Churchill was educated in part on the funds generated from the sex on sale in its property.
And it is in Shepherd Market that a symbol of a new Mayfair, challenging the traditions and fabric of the old, is rising. In the building which once housed the most notorious of Shepherd Market's drinking clubs, the Maisonette, the Qatari government has just won planning permission to convert two floors into a mosque.
"We have had plenty of people wanting to turn old churches into licensed premises," said a spokesman from Westminster City Council's planning department. "But this is the first time we have been approached by someone wanting to turn a licensed premises into a place of worship."
John Campbell is one of the residents of Shepherd Market who welcome the idea of a mosque. He is the proprietor of Tiddy Dolls, the traditional English restaurant in the middle of the Market, and has lived above the shop for 37 years. He remembers the Maisonette at its sleazy prime. Run by a woman called Ruby Lloyd, the club used to satisfy the needs of those who could not wait for opening time in the days before pub licensing hours were extended.
"My bank manager was a typical client," remembers Campbell. "I'd have a meeting scheduled with him for four in the afternoon and his clerk would very embarrassedly have to ring round to find out where he was. The first port of call would always be the Maisonette, and Ruby would pour him out into the bank. Poor soul drank himself to death. And every morning when I opened my curtains, I'd see Ruby standing outside her door failing to get her key in the lock. She'd been out all night drinking, which always seemed to me a dangerous hobby to have when you spend all day running a drinking club. She died of it, too, of course."
It was not just drinkers who were attracted to the Maisonette. At midnight there would be up to 100 streetwalkers outside, waiting for business from the regulars. Indeed at the height of the Market's (and the Maisonette's) notoriety in the late Seventies, commissionaires in the grand hotels of Park Lane would tell families of tourists not to go to Tiddy Dolls, such was the gauntlet of girls they would have to run.
"There was one occasion," Mr Campbell says, "when a gang of girls set upon and beat up an American tourist. They'd taken one look at her and decided she was a hooker trying to move in on their territory. Of course she wasn't, the poor woman was just a little blousey."
As is characteristic of vice areas, Shepherd Market was awash with gangsters and petty criminals. As well as some of the most corrupt policemen in the country.
"A girl was financing three people from the game as well as herself: her landlord, her ponce and the local police," remembers Mr Campbell. "Things became so bad that in 1978 we established the Save Shepherd Market Campaign and took a murder map along to the House of Commons. This showed the position of every murder, act of arson and defenestration of prostitutes that had taken place in the previous 12 months. It was a horrific document. Three days after that, I had my restaurant raided and turned over by the police. It was a public statement, not so much to me as to those who lined their pockets."
Concerted action by Westminster City Council, and by Scotland Yard in pruning the orchards of bad apples at its core, has seen much of this old Shepherd Market disappear. There are still doorways aplenty open at night, but the streetwalkers and their associates have moved elsewhere. In their stead have come a variety of restaurants, cafes and expensive eateries. The final confirmation of this shift in the area's fortunes might appear to be the arrival of a mosque at its heart.
Yet objections to the plans have been many, varied and loud. Sir Tim Bell, Lady Thatcher's media consultant, whose offices are just along Hertford Street from the planned mosque, wrote to Westminster Council complaining about the possible "increase in noise and pollution". Some locals worried about their peace being shattered by muezzins' chanting from minarets at all hours of the morning. And the Residents' Association of Mayfair, in a deposition to the council, argued against "the setting of a precedent".
"It appears to be the peaceable use of private property," says the association's president, Sir Michael Clapham, of the mosque. "But we as an association will fight all attempts to turn residences into any other use. We want to regain private residences in this area, that is the great thing we fight for."
Indeed this has been a battle that has been raging for the past 50 years in Mayfair. During the war, the aristocrats who lived in the area fled to their country properties. Afterwards, faced with the mounting costs of the modern, tax-happy era, few of them chose to return. Westminster Council granted the area's two biggest landlords - the Duke of Westminster's Grosvenor Estate and the Berkeley Estate (now owned by the BP Pension Fund) - 30- and 40-year temporary office permissions for many of their now empty buildings, to soak up some of the need for office accommodation caused by bomb damage in the City of London. Where once dukes and earls strolled, patronising the pricey stores, their servants keeping the pub tills busy, the streets soon became full of executives and businessmen. And on the rare occasions when residential accommodation became available, it was at a premium affordable only to the world's giga-rich.
"There have always been fads of interest from all over the world," says Peter Wetherell. "First the Americans, then the Greeks and the Indians. And from the Seventies the Arabs. We agents have been accused of selling the area out to the Arabs. But we are only acting on behalf of our clients, the English who wanted the best price for their assets."
Since 1990, as the temporary planning permissions have expired, one million square feet of office space has reverted to residential use. But the reversion has not included the mix of small, middle-sized and large homes hoped for by the residents' association. Peter Wetherell has on his books a house in Park Street which has just been converted from an office. It is, he says, the epitome of the Mayfair town house, with its dining-room floor made from antique oak stripped from old French railway carriages, with slab marble on the floors of the several bathrooms, and with a kitchenette in the master bedroom suite ("for keeping your croissants warm"). At a cost of pounds 4.9m for a 65-year lease offered by the freeholder (the Duke of Westminster) the buyer is unlikely to need a mortgage.
"It's fair to say that a buyer of this sort of property will be an international resident," says Peter Wetherell. "With homes perhaps in Monte Carlo and New York, a chateau in France and maybe an island somewhere. It is highly unlikely they will spend all of their time there."
Nor will they be the kind to join the Residents' Association and spend their spare time lobbying to keep the local library open. In ever-increasing numbers, the kind of person able to buy into this world is a rich Arab. And with them, they have brought their own lifestyle: one based around security, discretion, privacy. Walking around Mayfair, you see evidence of it everywhere. On South Audley Street, next door to Purdey's, the bespoke gunmaker, are two shops selling specialist spy equipment; the new Saudi embassy on Curzon Street boasts more closed circuit television cameras than Belfast crown court; the only sight you catch of the new Mayfairites is when they jump quickly into shops or houses from limousines the length of a small street. Between them, the new residents have the financial muscle to change the place to reflect their own tastes: if a private mosque is needed, to prevent the disagreeable need for rubbing shoulders with the merely rich at Regent's Park, a building can be picked up out of loose change.
It is this power that clearly disturbs some of those locals without it. That, and a racism which is publicly suppressed. One Shepherd Market resident, who asked not to be named, told of how "an Arab had tried to buy the pub: he said he wanted to shut it down because he objected to alcohol so close to where he lived. He had the money, too. That's what's happening here, the English are being priced out of it."
This however, is a vision of Mayfair that Peter Wetherell rejects entirely. "We did a survey last year, and 40 per cent of our buyers were British. Besides, a mosque in the Maisonette seems a jolly good idea to me. Better the worship of God than the worship of alcohol. As far as I'm concerned, Mayfair is a nicer place to be than it ever has been. But then I suppose I would say that, wouldn't I?"