The Mail on Sunday story refers to a separate legal case brought by the Duke against the Home Office. He is seeking judicial review of the Government's decision not to provide police protection for him and his family when they are in the UK.
The newspaper revealed he was taking legal action in an online story on the evening of January 15, and in print on January 16.
After the paper went to print, and shortly after it was posted on MailOnline, the Duke's team confirmed he was seeking judicial review, believing the UK to be unsafe for his family to return to, and noting: "The Duke first offered to pay personally for UK police protection for himself and his family in January of 2020 at Sandringham".
At that time, the Duke was discussing the details of his departure from official royal duties with his brother, father and grandmother at what has become known as the "Sandringham Summit".
When the court case had its first hearing on February 18, lawyers acting for the Government appeared to challenge that, saying the offer of payment "was notably not advanced to Ravec [the Executive Committee for the Protection of Royalty and Public Figures]" when the Duke visited the UK in June last year or in any of the immediate correspondence that followed.
In any event, the court documents note, "personal protective security is not available on a privately financed basis" and Ravec does not make decisions on security on the basis of payment.
The following weekend, the Mail on Sunday published a second story stating that "the revelations are a crushing rebuttal to Harry's initial public statement that implied he had always been willing to foot the bill".
In papers now filed to the High Court, the Duke's lawyers claim the court hearing "was no rebuttal at all to the claimant's public statement, let alone a 'crushing' one".
They argue it refers only to the Duke's dealings with Ravec, and not his offers of payment for police protection made to other parties.
The Duke "has been upset (but sadly unsurprised) by the defendant's distortion and misrepresentation of the facts in breach of the most basic journalistic standards and ethics," they say.
They object particularly to the suggestion that the Duke tried to keep his legal claim a secret, and the idea that he "improperly and cynically tried to manipulate and confuse public opinion by authorising his 'spin doctors' to put out false and misleading statements about his willingness to pay for police protection" after the Mail on Sunday story was published.
They also object to the word "Exclusive" being used to promote the story, its prominence on MailOnline, and the "numerous gratuitous photographs of the claimant and his wife and family".
'Considerable distress and hurt'
When the online article invited readers to "share what you think", they say, the public responded with more than 6460 comments, "the majority of which are adverse and hostile".
The "exceptionally serious and damaging" claims "constitute an attack on his honesty and integrity and undermine his fitness to be involved in charitable and philanthropic work in general, and in efforts to tackle online misinformation in particular (through the Archewell Foundation)", legal documents argue.
"It must have been plain to the [Mail on Sunday] that by giving these serious allegations such huge publicity in the terms and manner that it did, leading to inevitable repetition and the feeding frenzy of hostile comments, it could not but cause [Prince Harry's] reputation substantial damage and cause considerable distress and hurt to the [Duke's] feelings, as has been the case."
The Duke's lawyers asked for the story to be taken down from MailOnline.
It is alleged that the Mail on Sunday, in response, accused Prince Harry of "chill[ing] further discussion" and issuing proceedings for his own "media management purposes", "as part of his continuing self-declared battle with anyone in the media who dares to publish anything about him which is less than flattering".
As a result of the outlet failing to take the story down, his lawyers say, Prince Harry has "suffered increased upset and distress and injury to his feelings".
The Duke is seeking damages including aggravated damages for libel, an injunction preventing the Mail on Sunday from re-publishing defamatory statements, and publication of the High Court's judgment.
Associated Newspapers Limited, which publishes the Mail on Sunday, is defending the claim.
