The average price for a detached family home in London has hit £1m.
According to research by Hamptons International, families looking for a detached home in London now pay an average £1,028,376, up from £963,510 last year - an annual price increase of 6.7 per cent.
The disparity between the price of detached family properties in inner and outer London has also been growing over the past 20 years.
In 2015, the price went above £2m in inner London and this year stands at £2,086,259. This is more than double the average price a family would pay in outer London, where the average is £937,919.
But, the data from Hamptons International suggests that prices in central London may have plateaued. Recent research by Knight Frank showed that prices for high-end homes in central London fell by 2.6 per cent in September. In Chelsea, house prices have fallen by as much as 10 per cent year-on-year.
Fionnuala Earley, residential research director at Hamptons International, said detached family houses are becoming an "endangered species" in the capital.
"Today they account for less than five per cent of the capital's housing stock - a fifth less than twenty years ago," Earley said.
"The hotspots for these homes are in leafy south west and north London, but even there numbers are being squeezed by both the amount that have been converted into flats and the tiny numbers of detached homes built to replace them."