The head of one of the estate agents caught up in the latest cartel case has confirmed that his MP wife and her boss, housing minister Gavin Barwell, were both kept informed of the matter.

Charles Clark, partner and chairman of Greenslade Taylor Hunt, is married to Taunton Deane MP Rebecca Pow, who was last year made Parliamentary Private Secretary to Barwell.

The new edition of Private Eye says that Pow “has a spot of bother on the domestic front”.

In time-honoured fashion recognised by Guardian readers everywhere, the magazine manages to get Clark’s name wrong, but its piece in the HP section does mention the price-fixing cartel.

It concludes: “If Pow has not yet mentioned this to the Tory whips, she’d better hurry up: she is PPS to the communities department’s Gavin Barwell, minister responsible for, er, housing.”

Yesterday, Clark told EYE that his wife has never had any involvement with the prominent west country firm of estate agents, which has 17 offices. He also said that the cartel case revolved around just one of the firm’s partners, acting on his own, and without knowledge of other partners.

The Competition and Markets Authority earlier this month fined the firm £186,000 – the heaviest of the fines.

Altogether, four agents in Burnham-on-Sea, Somerset, were fined £370,000 for colluding to fix their commissions at 1.5%.

A fifth agent escaped being fined because it was the first to confess to its involvement; a sixth apparently remains under investigation although the CMA has underlined that no conclusions should be drawn.

Clark, a seventh-generation valuer and auctioneer, emphasised that while his own firm was clearly not happy with the fine it accepted the punishment; he stressed he has also had no argument whatever with the CMA investigation, with which Greenslade Taylor Hunt has fully co-operated.

Clark said: “We profoundly regret what occurred at Burnham-on-Sea.

“As soon as the CMA raised concerns we undertook a thorough investigation of all offices and departments.

“We are entirely satisfied that this issue resulted from the wholly misguided and inappropriate actions of one GTH partner, acting entirely alone, at one branch of our group and that no other office or department was involved in any way whatsoever.

“The partner’s actions at Burnham-on-Sea were undertaken with neither the consent nor knowledge of other GTH Partners or staff at any other office in our organisation.

“The partner concerned recognises that his actions were a gross misjudgement. He has apologised to his colleagues at Burnham-on-Sea and to the partners and staff throughout the firm for letting GTH and its clients and partners down in this manner.

“He is completely mortified, recognises his error and regrets his involvement in every way.

“Discussions are continuing as to the individual’s future responsibilities within the firm.”

Below, the piece in Private Eye – complete with the wrong name