Brighton and Hove's property boom could be over, with flat and house prices at a standstill for the first time in more than ten years.

Figures published today show the city's explosive market - which since 1999 has seen some homes triple in value and the cost of an average house rise by £100,000 - is at an end.

Estate agents are optimistic the slowdown is a temporary lull in an ongoing upward trend, triggered by fears of war, but there is evidence prices may have hit their peak.

Traditionally, the beginning of the year is a boom time for property prices but 2003 has not taken off.

Statistics published by property web site Hometrack show prices have not changed for three months with the most expensive houses remaining unsold and the cheapest flats proving too expensive for many first-time buyers.

Hometrack economist John Wrigglesworth said: "House price inflation remains subdued. There is no evidence of any spring revival in an increasingly moribund market."

The Royal Institution of Chartered Surveyors and the Land Registry have also released disappointing figures in the past few weeks.

Both bodies recorded falls in property prices in the last three months and predicted worse to come.

The cost of an average home in the city rose from £86,128 in February 1999 to £183,000 in November 2002.

The average flat increased from £63,212 to £133,000. A detached house went up from £149,391 to £327,000.

The threat of war has worsened the situation, with many would-be buyers preferring to stay put than risk negative equity.

While many estate agents say they are busy, houses are taking longer to sell and the asking price is often not met - leading to the overall slowing of the market.

Further worrying signs come from the Bank of England.

Deputy governor Mervyn King predicted house price inflation would fall from 25 per cent to 0 per cent by the end of 2004. Many parts of Sussex are already at that level, 20 months early.

Brighton estate agent Glenn Mishon, who says the year got off to a good start, admitted: "The future is very difficult to call because of the possible war with Iraq. Nobody knows what is going to happen over the next few months.

"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."

Prices in the sought-after Fiveways area of Brighton have enjoyed a typically steep rise in recent years.

Lynne Sturland, senior branch manager at the Preston Park branch of Bradford and Bingley-Geering and Colyer, said he was optimistic the market would pick up again.

She said: "We've had such a terrific rise. Over the last three years we've had 300 per cent in the area.

"We're not sure if prices have peaked - there's still a general background level of activity. But with the war situation there is an air of hesitancy around.

"It is a particularly cold snap of weather and so it may be people have decided to put things on hold for a while.

"With the spring on its way, we're optimistic this just may be a lull."

East Sussex is bucking the national housing slump with the fastest price rises in the UK.

The prospect of war in Iraq has done nothing to dampen the enthusiasm of the county's househunters, who have seen the cost of an average home rise £1,377 since January.

Prices rose by 0.9 per cent in East Sussex whereas the rest of the UK continued a nine-month decline in the property market, with a rise of just 0.1 per cent.