One property was recently sold for more than £7m
The housing market may have been fluctuating in recent months, but the most exclusive street in England and Wales remains unchanged.
Chester Square in London's Belgravia has an average property value of £6.6m and has topped a list of the most expensive streets for a second year.
Former Prime Minister Margaret Thatcher has a home in the street, where the average value is up £400,000 on 2009.
London dominates the expensive property league, the Mouseprice.com poll found.
Other notable residents of Chester Square, which is between Victoria and Sloane Square, have included Chelsea Football Club owner Roman Abramovich and Frankenstein author Mary Shelley.
The high-value area helped push up the average price of properties on the 10 most expensive streets to £5.5m in London, ahead of the £3.7m of the top 10 streets in the South East of England and £1.8m in the East of England.
Wales was bottom of the list with an average value of £676,320.
"Prices for the most expensive properties in the country have been fairly consistent with the middle tier of the property market," said Zipporah Morrison Baker, of Mouseprice.com.
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.