Clarence House has blocked a charity auction of Christmas cards sent by Prince Charles to a friend.
The cards showed Charles in a variety of different poses
Former journalist Charles Quant, from Flintshire, had Alzheimer's disease and died in June aged 88.
He led the Prince of Wales Committee in Wales, and his family hoped the sale of 24 cards could have raised thousands of pounds for the Alzheimer's Society.
But Clarence House, the prince's household, objected, saying the cards were sent on a "personal basis".
A spokesman said: "We were asked to approve the sale of these personal cards.
"The cards were private and sent on a personal basis. That is how we see them and that was our response to the Alzheimer's Society."
Mr Quant, of Gwernymynydd, was a columnist with the Daily Post newspaper, was awarded the MBE for services to the community and was a lieutenant of the Royal Victorian Order for his 25 years as a member of the Prince of Wales Committee.
Mr Quant was a founder member of the committee, which aims to improve the natural environment in Wales.
Over the years he collected 24 cards from the Prince of Wales, including one picturing Charles wearing a Native American head dress in 1977.
The cards were often addressed to "Charles and Mrs Quant," and signed "Charles".
Mr Quant helped found the Prince of Wales Committee
The sale had been planned for Tuesday by Fellow and Sons auctioneers and valuers in Birmingham.
Stephen Whittaker, managing partner, said the company "fully" understood why the family had withdrawn the cards from sale following correspondence from Clarence House.
But he added: "We are obviously disappointed as we were expecting these items to raise a significant amount of money and publicity for the Alzheimer's Society.
"We were waiving all usual buyers' premiums and fees on the day and other businesses were also donating their services free of charge so every penny raised would go to the charity."
Neil Hunt, chief executive of the Alzheimer's Society, said: "The Quant family has decided to cancel the sale which featured a collection of items of huge sentimental value.
"It is disappointing the event cannot go ahead but we respect the family's reasons."