Values of the capital’s high-end homes tumbled by 6.6 per cent in the year to April – the near fastest plunge since the financial crisis – showed research by Knight Frank.
Suburbs favoured by the some of the world’s richest people, such as Kensington and Chelsea have seen values tumble by more than 10 per cent from their post-recession peaks.
Overall, the number of exchanges in so-called prime central London sank by 11 per cent year on year in the first quarter of 2017, said Knight Frank.
The lettings market has also taken a hit, falling another 0.2 per cent in April, meaning rents are down 0.7 per cent in the three months to April and 4.7 per cent year on year.
And millionaire house prices are unlikely to improve any time soon, said the agent in a gloomy update.
Tom Bill, head of London Research at Knight Frank said: “While it seems likely sales will improve, it doesn’t seem plausible that the same will be true for prices, at least in the short-term.
“Buyers remain very price sensitive, although there is anecdotal evidence of isolated but growing instances of competitive bidding on properties.”
Between 2009 and 2013 price rises in wealthy London areas rocketed, hitting a peak in 2015.
Experts blame changes to stamp duty for collapsing the top of the market, after an extra duty on sales of second homes was introduced last year.
The UK election has also created a small degree of added uncertainty for the top-end of London’s property market, but is unlikely to have a large impact on sales or prices, according to Knight Frank.