Foxtons shares tumbled after a broker started covering the UK estate agency market, and gave the firm a “sell” rating.

Peel Hunt also issued “hold” ratings on Countywide, LSL and Savills.

Peel Hunt said it was gloomy about the long term outlook for agents, saying that fees would head downwards in view of competition from online firms.

It said the big issue was when commissions would fall, and by how much. It said: “Estate agents operating in London potentially face the greatest downside to commission rates given the absolute savings that vendors can make using a fixed price agent.”

Peel Hunt said that the general election had been good news generally for the market, ending uncertainty over mansion tax, controls on rents and the banning of tenant fees, and noting that comparatives figures from last year are set to ease in the second half of 2015.

However, it added: “While the near term news is positive and the listed players have diversified into areas with more stable revenue streams, we believe the sector faces longer term headwinds.

“It is still largely exposed to the highly cyclical nature of housing transactions and the growth of fixed price online estate agents is likely to lead to downward pressure, possibly significant, on industry fees and profits.

“The key issue is the pricing structure offered by the online estate agents which have been expanding rapidly and where the difference in fees is material – especially in higher value areas of the south east and London. The big debate for us is how far and how rapidly will fees fall.”

Foxtons last year charged an average commission rate of 2.4%.

Foxtons shares closed yesterday at 270p – some way down from their high of 315p a year ago, but up from last November’s low of 142p.