The livelihoods of smaller agents are under threat because of the charges of some suppliers to the industry – particularly portals.

Robert Sargent, CEO of one of the UK’s largest independents, The Acorn Group, said: “Profit margins are being eroded by service suppliers to the extent that the founders of smaller agents are daily wondering whether it is worth their while carrying on.”

He said that in a tough market for agents, “suppliers’ current costs are adding to the load” – a load which includes a poor housing market, high business rates, increasing legislative requirements, and the tenancy fee ban which has seen £800,000 disappear from Acorn’s own revenues.

He said that suppliers hiking their costs are ignorant of, or oblivious to, the strains that agents – particularly smaller ones – are already under.

Sargent said that the three portals – Rightmove, Zoopla and OnTheMarket – are all a cost issue for agents “in varying degrees” and particularly “when there’s a lot of duplication and as an industry we probably only need one of them”.

Rightmove has notified new price rises according to agents on social media at the weekend. One said his rates were being put up 11%, and another 30%, adding: “Who in the world can protect high street businesses over this?”

While Rightmove is defensive of its prices, Sargent said he would welcome the day when Rightmove told its shareholders that in the interests of sustainability, it would not be raising its costs to agents.

Asked if he could actually see that day coming, Sargent said: “Eventually it will, because it will have to.”

Sargent said that as a large independent which has no dependence on borrowing or external investors, he is constantly being approached by smaller firms wanting to sell.

He said: “We are speaking to numerous small businesses whose owners are considering a change of direction.

“Increasingly the motivation for them to sell is linked to the continual pressure of marketing costs, particularly the ever increasing costs of the various portals, which is a contributing factor to making their businesses harder to sustain.

“At the moment, I never have a deal off my desk. From a corporate perspective, it is great to have the opportunity, but I do understand how tough it is for the smaller firms.

“It is also not great for the industry as a whole: you need firms of all types and sizes, and for the competition to be healthy. The costs of entry to the industry are prohibitive and so, for many, are the costs of growing.

“That worries me. We need the industry to be diverse and sustainable.”

Acorn, which operates in around London, currently has 450 staff and 36 offices, after doubling in size since 2013.

It started as a one-office independent 35 years ago, and this year is on track to report profits of between £3.2m and £3.3m.

Next year, Sargent forecasts turnover upwards of £33m, with a potential doubling of profits.

The firm grows both organically and by acquisition.

It plans to open new branches, while more acquisitions which are all funded by the company’s own resources are in the pipeline.

The company has recently acquired Uniplan, in Sydenham, and has just bought Property In, a firm in Dulwich, south-east London, established almost 20 years ago.

The previous owners of Property In, Stephen and Helen Smith, do not cite rising supplier costs behind their decision to sell.

However, Stephen Smith said: “Since opening our doors, the industry has changed, and although we welcome the increased compliance and legislation, it has been taking me away from the core aspects of the job that I love.

“For my wife and me, it feels the right time to leave the business, and having known Acorn and their CEO Robert Sargent for almost as long as we have been in business, his company seemed a natural choice and one that would build on our reputation and provide an exciting home for my team.”

Acorn is taking on the agent’s four staff and the business will for the time being trade under its existing brand.

The group already has a number of brands, including John Payne, Langford Russell, Start Financial Services, and MAP Surveyors, and Sargent is a strong advocate of well-diversified businesses. The Acorn Group includes build to rent, commercial, EPCs, estate management, planning, surveys and leasehold services, alongside financial services, sales, lettings and property management.

Sargent says it is a flaw of online agents that they are not diversified: “They are mining a narrow seam – sales, some lettings and maybe financial services. If they want to survive they will have to offer a full range of services.”

He says that none of the online agents has yet produced a viable, profit making model, adding that Acorn is 100% committed to a full-service, high street model.

“We spend as much as any agent on online, but estate agency is a labour-intensive, advice-driven business,” he says.

It is also, he admits, a business that cannot stand still. Profits are constantly re-invested into the company; the effects of the tenancy fee ban, which took £800,000 off the balance sheet, have had to be countered; and Sargent admits that as a firm, Acorn is always looking to the future.

“We are not for sale, and we are not for flotation,” he said. “We are keen to remain independent. But I always have an eye open for the next opportunity.”