Strutt & Parker has halved its best-case growth forecast for prices in prime central London next year, while warning that values could at worse fall by 5%, as Brexit uncertainty continues to weigh on the market.

The agent had previously predicted 4% growth in PCL prices during 2019 in a best case scenario and zero at worst, but has now revised this to 2% at best or a 5% fall in a worst case situation.

It is also predicting that values across the UK will rise by 2.5% on average, the same as it has forecast for 2018, before hitting 4% annually up to 2022.

Stephanie McMahon, head of research at Strutt & Parker, said: “We are holding our forecast for UK growth at 2.5% for 2019 – with the five year forecast from 2018 to 2022 standing at 18%.

“Total transaction levels for England and Wales in 2018 look to be relatively equivalent to those in 2017, when looking at the country as a whole. We would expect this trend to continue into 2019 with the number of registered buyers and viewing numbers gradually increasing.

“However, the story in PCL is different and transaction levels continue to be low by historic standards.

“Substantial economic and political uncertainty remains both nationally and globally, and this does not look likely to change any time soon. The likely outcome of Brexit negotiations remains extremely unclear, with the potential for this uncertainty to continue longer than we hoped for.

“In London, we expect to see stagnant prices of further negative growth in the final stage of 2018 with the possibility of further price decreases continuing into 2019.

“Beyond 2019 it is extremely difficult to forecast the market with any certainty and we would expect some bounce back once more stability has returned. The fundamentals of the UK economy remain broadly positive, with sentiment remaining cautious.”