The final decision has now been published in full by the Competition and Markets Authority in the so-called agents’ cartel case – presenting evidence that lays bare what was going on, with a series of emails not seen before.

The document runs to 223 pages, covering the agents in Fleet, Hampshire, their local association and a local newspaper which between them agreed that fees should not be published.

The emails – reproduced complete with the original spelling mistakes – also show the amount of control being exerted not just over advertising but also editorial in the local newspaper’s property supplement.

One email from Hamptons threatens to cut its advertising by half after a reference to another agent’s fees slips through the editorial net.

In the same email, Hamptons also says that the association will now go back to considering the launch of its own newspaper.

Another email tells an agent that “advertising any rates, whether it be sales commission or rental, is prohibited as a member of the Association, I must ask you to stop advertising your fees with immediate effect”.

The agents, Three Counties, Waterfords, Castles, and Countrywide firm Hamptons, have all been fined, as has the Three Counties Estate Agents Association and Trinity Mirror title Surrey & Hants Star Courier. All have less than a month to pay their fines in full.

The document shows just how long-running the case has been, with the first complaint received in 2008 by the then Office of Fair Trading.

The OFT was sufficiently concerned to raise issues with the Three Counties rules, gave the association advice and apparently believed that one of its rules – Rule 21 – had been removed. However, it appears the rule banning the advertising of fees was not removed.

It was a complaint in 2013 raising concerns about the Three Counties Estate Agents Association and its relationship with the local paper that sparked the investigation which started in December that year.

The investigation’s final document, likely to elicit sharp intakes of breath, includes interviews with the participants, emails and references to conversations, and changes in Three Counties’ rules.

For example, at one point the original terms and conditions were changed, apparently to give dispensation to online agents, to say: “Members shall not, unless granted a waiver by the Committee in writing, advertise any sales commission rates whether directly or indirectly in the Property Paper and shall obtain the express approval of the Committee for any proposed advert … which in any way contains reference to a promotion, reduction, fee, special offer or discount… Any waiver … will only be granted in exceptional circumstances and only where the advertiser has no shop fronted premises at all in the area covered by the paper.”

However, one agent who wanted to include customer quotes in their advert, including “The fact you only charge 0.8% is an added bonus”, received an email saying: “You should also be aware that I am getting grief from other agents about the fact your [sic] allowed to advertise your fees & ‘why can’t we’ comments are coming through.”

It was then decided that no member agent of Three Counties should be allowed to advertise their fees.

When the same agent then asked whether the revised rules would allow them to advertise “We won’t be beaten” on price, committee members suggested during email correspondence that the rule should be extended to prohibit any direct or indirect reference to fees, as well as the fees themselves.

Another email, sent from Hamptons to an agent wanting to open a new office offering 0% commission for three months, said: “I would bring to your attention, with the rules of member of the 3 Counties Association, Section 21, making reference to advertising sales or letting commission rates and trust that if you decide to join the 3 Counties Association to benefit from the reduced advertising rates, this section of our rules is adhered to”.

Hamptons also wrote to the local newspaper saying: “I am aware that [Current Member C] are soon to launch new/rebranded offices in Fleet and Yateley and they are offering 0% fees to entice new clients to them, please can we ensure that the likely promotion advertising in the Courier over forthcoming weeks has no reference [to] fees.”

Another damning email, this time to members of Three Counties, said: “We have negotiated a fantastic deal with the Courier which includes substantial savings on current advertising exclusive to the Three Counties Members… I am pleased to say that the paper have now agreed not accept advertising from any agent who advertises rates.

“The Courier have agreed the above terms provided we sign a 3 year agreement with them.”

Yet another revealing email was sent by Hamptons to the local newspaper in 2013, saying: “I am frustrated that not withstanding our numerous conversations, a half page editorial featuring [an agent] promoting their ‘Pick and Mix’ service ‘at a fraction of the cost of a conventional agent’.

“With immediate effect Hamptons will reduce their advertising this year by half and I expect you to resolve this immediately, I will in the meantime be taking steps to re-engage the 3 Counties discussions to produce our own newspaper.”

The equally revealing reply from the local paper was: “The original press release that came in had references to fees and other services. They cut the bulk of the editorial sent. This sentence was missed on this occasion.

“Editorial have been vigilant for the last few years on cutting any reference … We apologise that it happened this time and editorial have assured that further checks will now be in place.”

In the case, Hamptons – together with Countrywide – were fined £349,473; Hamptons itself was fined £232,982; Waterfords was fined £46,186; Castles was fined £46,186; Three Counties was fined £90; and Trinity Mirror was fined £91,257.

All of the penalties must by paid in their entirety by July 13.

It is understood that the CMA is investigating a number of similar cases.

The full document is here