The survey says Chester Square is the most expensive in England and Wales
It is the street that the credit crunch forgot - Chester Square in London's Belgravia has an average property value of £6.2m, a survey suggests.
With its manicured gardens and residents including ex-Prime Minister Margaret Thatcher, it is the most expensive street in England and Wales.
One property was recently sold for £20m, according to Mouseprice.com.
The property website says London dominates the wealthy property league, although average prices have dipped.
It found the average value of homes on the most expensive street in London in early 2009 had fallen from a year earlier, down from £6.8m.
One Chester Square property currently on the market for £13m features five bedrooms, four bathrooms, a roof terrace and a gym - all air conditioned.
Top prices by region
Greater London: £4.851m
South East: £3.3m
North West: £1.647m
South West: £1.347m
West Midlands: £1.067m
Yorkshire and Humber: £1.008m
East Midlands: £847,560
North East: £810,590
Source: Mouseprice.com. Average value of the ten most expensive streets in each area
The buyer can look out at the Georgian terraced homes and the police-guarded property of Lady Thatcher, or the former home of 19th century poet and cultural critic Matthew Arnold.
"The most desirable streets are suffering from falls in property values. However, this year's number one road has experienced some credit crunch-defying sales," said Mouseprice spokeswoman Zipporah Morrison-Baker.
She said that the affordability of UK property to international buyers had improved owing to the falling value of the pound, but high-end properties were not generally immune to the market slump.
"Price falls for the most expensive properties in the country have been fairly consistent with price falls for the middle tier of the property market," she said.
The next five streets listed in the price rankings were all neighbouring the Hampstead and Highgate golf courses of north London, all with average property values of more than £4.5m.
Margaret Thatcher has a home on Chester Square
There is a stark difference between different areas in England and Wales.
The average value of properties in the ten most expensive streets was highest in Greater London - at £4.8m. This was followed by the South East (£3.3m) and the East (£1.7m) of England.
At the other end of the scale the average value of properties in the ten most expensive streets in Wales (£716,090), the North East of England (£810,590) and the East Midlands (£847,560) all failed to hit the £1m mark.
The survey was based on Land Registry sale price statistics and updated with valuation data gathered from surveyors. Average values were narrowed down to postcode level using an automated system.