Prime London residential prices fell by 3% in Q1 2018 while the average discount to asking price was 12.1%, according to new research from Coutts.
The bank said sales volume fell by 24% compared with the same period last year, and is down by 33% on the 2013 peak.
Sales volumes and pricing had seen a slight increase at the end of last year, leading to hopes the market may recover.
However, the glut of prime properties on the market, notably those nearing completion or built, has further dampened prices.
At the beginning of the year, Barratt London halted the second phase of its Fulham Riverside scheme owing to the prospect of unsold stock.
In an application to keep its current sales pavilion open longer Barratt said: “Despite phase 1 of the development now being complete, phase 2 has experienced significant delays in implementation, largely owing to a downturn in the London housing market.
“As a result, proceeding with phase 2 in line with the original construction programme would substantially heighten the prospect of Barratt London having unsold stock, which clearly would not be commercially attractive.”
Across London however, discounts and sales rates vary considerably. While some of the challenger prime markets have seen large discounts in the past 12 months, this is partly because more established areas had reported greater declines.
Some 53% of prime property on the market sold below the asking price, compared with 42% last year.