Diana, Princess of Wales, was more "predatory and skilled" than her husband as they waged war with each other in the media in the 1990s, an official claimed at the time.
Staff who worked for her "devoted a great deal of time to finding ways and means of upstaging St James' Palace", they added.
The assessment from 1995, while the royal couple were separated before divorcing a year later, has been made public as part of an annual release of documents from the National Archives of Ireland.
The then Prince - now King - Charles, visited Ireland in June 1995 as part of a strategy to give him a more positive public profile.
His team regarded the trip as a success, calling it the "best public outing the Prince has had in a very long time".
Department of Foreign Affairs official Joe Hayes wrote that the prince's press secretary, Sandy Henney, told him she expected Diana's team would shortly be in touch to arrange a trip of her own.
"I took this as a joke until she repeated it and assured me that in the media battle between the two, the Princess was by far the more predatory and skilled and her staff devoted a great deal of time to finding ways and means of upstaging St James' Palace," he added.
At the time there was an intense briefing war between the separated couple. In 1995 Diana gave a BBC interview in which she declared there were "three of us in this marriage," a reference to Camilla Parker Bowles, now Queen Camilla, who married the King in 2005.
Diana, Princess of Wales, died in a car crash in Paris in 1997.
(c) Sky News 2025: Diana, Princess of Wales, was more 'predatory and skilled' than Prince Charles in media war
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