As the giant front doors open, Brighton and Hove's most expensive house reveals a welcoming, sparkling expanse of heated marble floors and polished oak panelled walls.

A double staircase leads to the first-floor gallery landing.

It is a stunning property, which the owner spent ten years trying to buy, 18 months negotiating a deal on and more than £1 million renovating.

Bought in near-derelict condition more than a year and a half ago, an oasis of luxury beyond most people's imagination has been created on the hills of Roedean in front of East Brighton Golf Course.

The indoor heated swimming pool overlooks an outdoor heated pool, near the garden's giant ornamental fish pond and fountains, all of which are near to manicured gardens, the marina and the English Channel.

Estate agent Glenn Mishon said: "The truth is, we've never had a house of this quality on the market before. It is the best house in Brighton and Hove."

But although the city's booming property market rose 18.7 per cent last year, some of the most expensive houses have sat gathering dust as their asking prices power beyond the reach of all but the richest elite.

Many estate agents privately admit properties on their books could be overpriced, an ongoing problem since last summer, which has worsened with a slowdown in the market.

The problem stems from a gulf between buyer and seller expectations.

Sellers, having heard about record increases in house prices last year, often expect their house to be worth more than it is. Buyers frequently cannot afford it and the market begins to slow.

Even those who could afford it have baulked at Roedean House's £3.5 million price tag.

It went on sale last summer for £4 million.

Since November, ten potential buyers have seen it but none have stumped up the cash.

The house's luxury trappings, such as the 60ft master bedroom, incorporating dressing rooms, a marble-tiled Roman bathroom with jacuzzi and open-plan shower, make it worth the money, says Mr Mishon.

The lower ground-floor of Roedean House epitomises its luxury lifestyle.

The snooker and games area leads into the health complex, with a sauna and steam room, a heated sunken 40ft swimming pool, a six-person flotation and massage room, a gym and changing rooms. Fibre optic mood lighting and a fully fitted bar complete the rock star effect.

Mr Mishon said: "It is certainly the best house in Brighton and Hove and arguably one of the best in the country. There are very few houses anywhere of this quality, that have sea views and back on to a golf course.

"Certainly you can get more land for your money but, for the complete package, there is very little to match this.

"Cate Blanchett has already moved to Brighton and this is the sort of property which could easily attract another huge star. "

It is a measure of the city's popularity, its lack of available properties and the housing boom over the last few years that such a price is being touted. But has the boom been too big?

Country Life magazine reported last week interest in homes costing over £1.5 million in Sussex and the South-East fell sharply in the last three months of 2002.

Between April and July last year 57.3 per cent of inquiries on its web site were for top- priced homes. Between October and December that fell to 14.4 per cent.

A slowdown in the sale of the most expensive homes is often the first indicator of how the rest of the market will react, suggesting the happy times for homeowners could be ending.

Another indicator house prices in Sussex are near their peak is that the county normally follows London trends.

Since September, houses in London have become increasingly difficult to sell, spending twice as long on the market as in the summer and much longer than other parts of the country, according to property web site Rightmove.

But the stock market and London's property market are far more closely linked than in Brighton.

When City high-fliers take home big bonuses they tend to invest heavily in expensive London property but when times are bad, as they are now, the opposite is true.

Mr Mishon said: "There is still a market for top-end houses if they come on at the correct value. There are certainly people looking if the price is right. Everybody has tried to talk the market down and it hasn't happened.

"The future is very difficult to call because of the possible war with Iraq. Nobody knows what is going to happen.

"I think it will affect the housing market because more people will sit tight and see what happens.

"But if there is a war, and if it is a quick in and out affair, I don't think it will cause a long-term problem."

Almost all experts agree the rapid price rises of the last couple years must end - it is simply a question of how.

The worst-case scenario is a dramatic "boom and bust", which would mean negative equity and repossessions.

At best there will be a soft landing, with prices remaining stable for a while or dropping slightly before bouncing back.

Throughout last year, interest in properties under £1 million consistently increased, while interest in properties over that mark decreased.

Properties above £3 million suffered the biggest fall in inquiries.

But swathed in the comfort of Roedean House, the economic vagaries of the outside world would feel a long, long way away.