Agents have been warned that their reliance on Rightmove and Zoopla means risking their own businesses.

Paul Smith, CEO of Spicerhaart and a director of Agents’ Mutual, said: “As agents, our reliance on Rightmove and Zoopla carries significant risk to our businesses, livelihoods and our entire industry so it is essential that we take a stand now.

“We are all guilty of handing over the responsibility for our web leads, traffic and our inventory to the portals, and as a result we have created the duopoly which exists today.

“We have provided a lot of shareholders with enormous dividends, and as our own industry faces increased competition from online players.

“We cannot afford to hand over any further power to the portals or we will weaken our position and increase their dominance.”

Smith also said that OTM, now coming up to its first birthday, would focus on the needs of the consumer by “providing them with what they need – a simple and well-designed website which displays properties in the best possible light”.

He said the site “has already become familiar to millions of property-seekers across the country”.

Smith went on: “Support across Britain’s traditional estate agents continues to grow for this 100% agent-owned and agent-controlled portal.

“It is providing high-quality leads to its members and in our own case, OnTheMarket provides us with a high level of genuine enquiries from motivated sellers and landlords.”

He said: “Spicerhaart voted with its feet and was proud to back OnTheMarket from an early stage.

“It remains a committed board member firm of Agents’ Mutual because we want to control our own future.

“Agents joining OnTheMarket have the ability to fix their fees until 2020 and as a mutual without shareholders, OTM will ensure its focus remains on the consumer.

“Led by an experienced executive team – in whom we have every faith – we believe that OTM will achieve what it set out to do by becoming a genuine alternative to Rightmove for estate agents and consumers.

“As the portal approaches its first birthday, it’s clear that it has achieved a great deal in just 11 months, so imagine what it can achieve throughout 2016 with its growing levels of support.”