Something strange has happened to central London’s most elegant neighbourhoods. In broad daylight, Mayfair, Knightsbridge and Belgravia remain as vibrant as ever; after sundown, though, it is a different story. As the street lights go on, whole terraces of windows remain dark.

These are London’s ghost ghettos, occupied either as pieds-à-terres by inhabitants of the home counties or lived in for only a few weeks each year by a shifting population of the world’s super wealthy.

In property, as in most things, the rich get richer. For London’s most prestigious addresses can be relied upon to hold their value when nearby streets are falling in price, and to go up at a faster rate than their neighbours when prices are on the rise — even though they are empty much of the year.

“London’s trophy addresses have a cachet beyond their intrinsic value,” says Ed Mead of Douglas & Gordon. “They are owned by very wealthy people who usually live out of town or abroad. These places are a good hedge against a falling market and are always going to be ahead of the game when the market is rising.”

He points out that £1,000 per square foot had become standard in Chelsea and South Kensington before prices were hit by the stock-market crash that followed September 11 last year. Now there are only five addresses that can be relied upon to command such prices: four with SW1 postcodes — Eaton Square, Cadogan Place, Cadogan Square, Hans Place — and Onslow Square, SW7.

Mead acknowledges that these areas, “deserted after 6pm and terribly clean”, may be too antiseptic for some.

Andrew Scott of Lane Fox estate agency says: “Certain areas are sad victims of absentee owners. This is typified in the ghost-town atmosphere of Chelsea Harbour, where as many as 60% of flatowners keep them as second homes.”

Flats in Chelsea Harbour, a 1980s marina development, cost from £450,000 for a “dismal two-bedroom flat with no view” to £2.5m for a place “with a 360-degree view over all of London,” says Scott. “The proportion of people who own flats in premier locations such as Lowndes, Cadogan and Eaton Squares but don’t live in them is 30%, possibly even as much as 40%, of whom 95% will have a second home elsewhere.”

Jenny Moores is a 33-year- old American who lives in a high-rise apartment in San Diego, California. She also owns what she calls a beach house — though it could be termed a mansion — in Del Mar, California, and a flat on top of the Park Hyatt hotel in Beaver Creek, Colorado. When in New York she makes do with the Ritz-Carlton. Last month she bought a town house in Marylebone, central London, and now she is buying a house in Mayfair.

“I’m a trust-fund baby who got lucky,” she says. “I have a father who worked hard. He started with nothing and went into the computer industry a long time ago. I was given stock options they thought would never amount to much and they happened to boom.”

Moores is now extremely rich. She is a shareholder in the San Diego Padres baseball team — her parents are the majority shareholders.

“I am the only female owner in baseball who bought it herself. The others are wives,” she says. She has also invested in the London-based Mayfair Agency, an image consultancy that caters for the rich, the famous and the frantically busy. It means she is in London for three or four months a year. And it was getting to be expensive.

“Last February I spent a month at the Metropolitan, at £225 a day,” she says. “Frankly, it made more sense to buy — and I love London.”

She enjoys having her street to herself after dark. “At night it’s quiet. There is nobody across the way, just darkened windows. It becomes something like a ghost town.”

Michelle O’Leary, of Aylesford & Co, sells flats in the £1m to £5m range — many of which are empty most of the time.

“A high proportion of flats in SW1, around Eaton Square, are second homes,” she says. “Prime residential properties don’t come on the market often, as people keep them in the family for occasional use. They are also popular with Arabs who come in the summer to get away from the heat, and for the racing.”

But it’s not just the very wealthy who fall for the charms of a part-time central- London pad. Anita Taylor, 61, runs a gift shop in Covent Garden with her husband. She lives in Harrow, north London, and has bought a time-share flat in Mayfair. For £85,000 she gets 28 days a year until 2050 at 47 Park Street, a former hotel with a side entrance to Le Gavroche restaurant that has been converted into apartments. Taylor may not always get the same flat every time she visits, but before she arrives her personal knick-knacks will be put out and the fridge stocked with her favourite nibbles.

“I will use it for business meetings. I can let it for one or two nights and it will be a nice little income,” she says.

Finance is usually a factor in the part-time home. Andrew Scott says: “Over the past 20 years, property prices in these areas have gone up 10% each year on average. So if you spend £2m on a place, it will earn £200,000 a year, and that’s a pretty nice reward.”

A Middle Eastern client of his bought a flat in Lowndes Square in 1993 for £550,000. “He refurbished it and staffed it for five years,” he says. “Two Rolls-Royces were delivered to the garage with seven miles on their clocks, and every room had fresh flowers every day. In those five years the owner spent just three nights there, and he eventually sold, in 1998, for £1.8m. The Rolls-Royces had seven miles on the clock.”

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