Foxtons’ property sales have plunged by a third in just three months as London homeowners shy away from transactions in the wake of higher stamp duty rates and fears over the Brexit vote.

The estate agency, which blamed a profit warning in June on the EU referendum, said revenue from property sales dropped 34pc in the three months to September 30 to £12.2m as it contended with lower transactions in the capital.

Higher rates of stamp duty, announced by the former Chancellor George Osborne last year, took effect in April, adding a 3pc surcharge on second-home buyers and buy-to-let investors.

It has hit London property owners in particular: average prices in the capital have now reached £489,000, compared with a country-wide average selling price of £219,000 in August 2016.

“We have built Foxtons to withstand sales market cycles,” said Nic Budden, chief executive. “The long-term fundamentals of the London property market remain very attractive and represent a huge opportunity for growth.”