Savills and Knight Frank say prime central London property values dipped slightly over the summer with stamp duty still being blamed for the enclave's faltering performance.
The high-end agency says prime central London average prices dropped 0.4 per cent - meaning annual prices for PCL have dropped 4.6 per cent in total.
"The increased transactional costs over £1m have undoubtedly made buyers more cautious, off-setting any post election euphoria, particularly as the stamp duty change came when parts of the market were beginning to look fully priced after five years of steady growth," says Lucian Cook, head of Savills' residential research.
“For all but the very best-in-class properties, many buyers are expecting a discount on last year’s prices at least equivalent to the additional tax. By contrast, stamp duty changes have benefitted properties in lower tiers of the prime market, which have performed more strongly.
Cook claims that prime London "now looks fully taxed" and admits that buyers' slowness in committing to purchase "is likely to continue to constrain the market in the short term."
Meanwhile Knight Frank's London head of residential research Tom Bill says “there is a discernible impact on the prime central London market” as a result of the increase in stamp duty for very high priced properties.