The latest data from Knight Frank suggests that average prices in prime central London dropped 0.7 per cent in the year to the end of January.
The agency says this is evidence that the annual declines recorded over the last 20 months have bottomed out.
The firm has also analysed supply and demand indicators over the last five years and says this, too, indicates that 2017 marked a turning point for the prime central London market.
In the rarified sector for homes valued at £10m or more, prices recorded a 0.2 per cent rise in the year to January, the first increase recorded in this price bracket for almost two years.
The largest rise in sales volumes by price band was 14.3 per cent over the past 12 months for properties valued between £5m and £10m.