Chestertons, one of London’s largest estate agencies, has announced that it will be advertising on the Zoopla and PrimeLocation websites from January.

In contrast, Savills has said it will drop Zoopla and use Rightmove as its “one other portal”.

Both firms are founding members of Agents’ Mutual and will be listing properties on OnTheMarket.

Chestertons, which has 30 offices across London,  is the first major estate agency company to announce choosing Zoopla over Rightmove as its “one other portal”.  Knight Frank and Spicerhart have both opted to drop Zoopla and go with Rightmove.

Chestertons – whose announcement came via Wriglesworth, Zoopla’s PR agency – said that one of the main reasons for choosing Zoopla is that in London, Zoopla and PrimeLocation have “substantial market share”.

Robert Bartlett, CEO of Chestertons and a founding director of Agents’ Mutual, said: We have looked carefully at data collated over the past 12 months and the numbers clearly show that our properties get more views and our clients get more leads from the Zoopla and PrimeLocation websites when compared to other property portals.

“Based on our analysis of the data, this was an easy choice for us.

“On top of this, we have all been impressed with the speed at which Zoopla Property Group has been able to grow over the past few years and, from working closely with them over recent months, know them to be an exciting and dynamic partner that is always looking for new ways to improve its website and service offering.

“The strength of the Zoopla and PrimeLocation brands in London and the south-east is clear and our clients expect to see their properties advertised on these websites.

“We look forward to continuing to work closely with the Zoopla team in 2015 and beyond.”

Savills spokesman Paul Jarman, however, said that having analysed leads generated from portals, the inquiries from Rightmove were higher quality than those from Zoopla. It was therefore dropping Zoopla. Savills has some 110 branches.

Three remaining Agents’ Mutual founders, Douglas & Gordon, Glentree Estates, and Strutt & Parker, have yet to say whether they are sticking with Zoopla or Rightmove.