Nephews of billionaire property magnate Sir Frederick Barclay have accused the octogenarian of “consistent, misleading and damaging briefing” against the family.

In a rare public statement underlining the acrimonious civil war dividing the Barclays, Aidan and Howard Barclay, sons of Sir Frederick’s twin brother Sir David, hit back at claims they sold London’s The Ritz hotel to a Qatari buyer in March for “half the market price”.

It is the latest episode in an increasingly bitter dispute engulfing the fractious family, which has seen Sir Frederick launch a High Court battle against three of Sir David’s sons, Aidan, Howard and Alistair, over secret recordings made at the famed London establishment.

Earlier this week, Sir Frederick released a video which he said showed Alistair handling a bug placed in the conservatory of The Ritz which he said was part of a “deliberate and premeditated invasion” of his privacy.

In a statement through Ellerman, the company behind the Barclay family’s assets, Aidan and Howard said: “Sir Frederick’s conduct relating to The Ritz sale process has been particularly concerning.

“Despite having no relevant legal interest or involvement, Sir Frederick has used the media to issue unwarranted threats of legal action which risked disrupting the process.

“It is simply untrue that any bidder made any formal offer for The Ritz of anything close to £1.3 billion.

“Had there been such an offer, we would have been delighted to accept it.

“But in the unanimous opinion of the independent advisers who ran the process, the successful bid was the best and most deliverable offer on the table.”

The statement said they had intended to “resolve our differences with Sir Frederick” in private, but felt they were left with little choice.

It said: “We have, until now, resisted making public statements to the media regarding them (Sir Frederick and his daughter Amanda) and the legal proceedings.

“However, due to the consistent, misleading and damaging briefing to the media against us and our family businesses by Sir Frederick, we feel it is necessary to set the record straight.”

They said they would “actively pursue our options for recourse against Sir Frederick”.

Sir Frederick and daughter Amanda are suing the three brothers, Aidan’s son Andrew and Philip Peters, a director of a number of family companies, after the “elaborate system of covert recording” came to light in January.

At a High Court hearing earlier in May, the pair’s lawyers claimed that The Ritz had been sold for “half the market price” after conversations between Sir Frederick and a Saudi investor, who was offering £1.3 billion for the London landmark, were secretly recorded.

In a statement, Sir Frederick said: “I find this statement baffling. My nephew Aidan persuaded me to find buyers for The Ritz hotel. This I did, getting not one but two substantial offers of more than £1 billion.

“We too would have liked to have resolved this in the family.

“Regrettably, this statement issued on behalf of my nephews is inaccurate, inept and ill-informed.”