The claim: In February 2015, Alex Chesterman, CEO of Zoopla, said OnTheMarket.com would be ‘a short-term event’

 Ian Springett: Nothing could be further from the truth. The fact is that our agent membership is growing week-on-week along with the number of property listings and our traffic. In August, we achieved more than 5.4m visits.

We are at the start of a new long-term strategic venture, one that will take time, but with the excellent support received from our agent members we have every reason to feel confident.

As well as the millions of visitors that are now coming to the site, we are delivering quality leads to our members and already, in some parts of the country, OnTheMarket displays more properties than Zoopla.

We remain confident that it’s only a matter of time before we overtake Zoopla as the No. 2 portal in terms of property listings and then focus directly on providing agents and consumers alike with a credible alternative to Rightmove.

Around 90% of our member agents have chosen to retain Rightmove as their one other portal and we have heard from many of our member agents that dropping Zoopla has not made the slightest difference to their businesses.

Far from being ‘a short-term event’, Zoopla’s investors and management should be in no doubt that OnTheMarket is going from strength to strength in a very challenging market and is here to stay.

We believe there is now a clear choice for agents. There is a very dominant market leader. Now is the chance for agents to develop an effective alternative to Rightmove which works for them.

Rightmove’s current share price of £37.13 compares with that of the No. 2 portal, whose share price is down from 263p on September 1, 2014, to 218.80p on Friday (September 11, 2015) despite all the hype around its acquisition of uSwitch.

The claim: In July 2015, Russell Quirk, the CEO of online-only agency eMoov, said OnTheMarket.com had failed to gain any meaningful inventory

Springett: From a standing start we have created a compelling challenger brand and business with hundreds of thousands of properties for sale and to rent at all price points across the UK.

The majority of these listings were effectively removed from Zoopla Property Group’s inventory. Our national PPC and advertising campaign – which runs across a range of press titles, websites and TV channels – continues to deliver very strong growth in traffic and our property stock is continuing to increase all across the UK.

What’s more, many of our member agents are choosing to list their new-to-market properties at OnTheMarket exclusively for 24 hours or more ahead of advertising them on any other portal.

This gives the most active property-seekers an extra reason to visit the portal, and to keep returning, in order to give themselves an edge in their search.

The claim: Zoopla Property Group has continually distributed Hitwise data regarding OnTheMarket’s traffic, showing a significantly lower figure of visits than those recorded by OnTheMarket. Who is right?

Springett: Our traffic is monitored using Google Analytics, a leading website tool also used by Zoopla itself.

We note that both Rightmove and Zoopla rely on Google Analytics to report credible, accurate traffic data to the market.

Hitwise relies on a panel and can only claim to provide an indicative representation of a website’s market share. It can produce misleading results and can certainly not be used to report accurately the absolute level of traffic to an individual website.

Our detractors are presumably well aware of this.

To put OnTheMarket.com’s traffic into context, it took Zoopla three years to reach 5m visits per month, even having acquired PropertyFinder, Hot Property and ThinkProperty along the way.

Even taking into account how the portals marketplace has grown since that time, the fact is that OnTheMarket’s 5.4m visits in August in such a fiercely duopolistic marketplace is a tremendous achievement.

The claim: In October 2014, Russell Quirk said OnTheMarket would ‘work to the detriment of the consumer with regard to excluding online estate agents’. He said ‘OnTheMarket would be anti-competitive in its approach to singling out which portals a member is permitted to list on’ and he has referred to the ‘one other portal’ rule as ‘cartel-like’.

Springett: There is nothing anti-consumer about OnTheMarket. The other portals feature properties from online-only agents, many of which are low-cost and offer less service and advice than high street agents, but consumers are unable to see the difference in the listings.

Because of this, property-seekers can find themselves negotiating directly with the home owner ​with no warning of what to expect.

OnTheMarket believes consumers should be clear what they get when they make a choice between a local, office-based, full-service agency and an internet-only ‘agent’.

Because every property listed with us is on the market with a full-service estate or letting agent, property-seekers, as well as vendors and landlords, can have confidence that the agents can provide a wealth of experience and local market knowledge, a full end-to-end service and the opportunity to deal face-to-face.

Furthermore, recent research has indicated in any event that online-only agents only account for approximately 5% of the total inventory on Rightmove and Zoopla. Would online-only agents consider it “to the detriment of the consumer” if a portal displayed only properties from online-only firms?

It is precisely because OnTheMarket is agent-owned and agent-controlled that consumers are able to relish a clean and responsive website uncluttered by adverts or widgets and devoted to selling properties clearly and efficiently.

The agents who own OnTheMarket know that the properties themselves are the “stars”, which is why, unlike the other portals, we do not carry third party advertising.

The OnTheMarket digital platform is fully responsive and state-of-the-art. According to independent Alexa statistics, OnTheMarket.com loads considerably faster than either Rightmove or Zoopla. What’s more, OnTheMarket has a clear additional consumer benefit in that many of its member agents are choosing to upload their new-to-market properties 24 hours or more ahead of the other portals.

The disruptive influence and service of OnTheMarket are positively pro-competitive.

With our launch, our members have created more choice for consumers and agents alike and are pursuing a longer-term strategy to prevent an unhealthy dominance and control of the portals market by just two firms. These two firms generate super-profits on the back of the data provided by traditional estate agents and provide the essential platform on which an ever-growing number of online-only agents depend.

The fact is that the Competition and Markets Authority considered Mr Quirk’s challenge and saw no reason to take action.