The Duchess of Sussex’s handwritten letter to her estranged father does not belong to the Crown, lawyers acting on behalf of the Queen have told Meghan’s legal team.

At the latest hearing in the duchess’s case against the publisher of the Mail On Sunday, the High Court heard that lawyers representing “the Keeper of the Privy Purse, acting on behalf of Her Majesty the Queen” told Meghan’s solicitors they “did not consider the Crown to be the copyright owner”.

Meghan, 39, sued Associated Newspapers Limited (ANL), the publisher of the Mail On Sunday and MailOnline, over a series of articles which reproduced parts of a handwritten letter sent to Thomas Markle, 76, in August 2018.

She claimed the five articles, published in print and online in February 2019, misused her private information, infringed her copyright and breached the Data Protection Act.

This unequivocal statement of Mr Knauf’s position also gives the lie to the defendant’s inferential case... that the claimant considered using the letter 'as part of a media strategy'

In February, the High Court granted Meghan summary judgment in relation to her privacy claim, meaning she won that part of the case without having to go to trial, as well as most of her copyright claim.

At a remote hearing on Wednesday, Lord Justice Warby was told that the Keeper of the Privy Purse’s lawyers had written to Meghan’s solicitors “disclaiming any claim to copyright on behalf of the Crown”.

In written submissions, Ian Mill QC, for the duchess, also said Jason Knauf – formerly communications secretary to the Duke and Duchess of Sussex, whom ANL previously said may have been involved in writing the letter – has “emphatically” denied being a co-author.

Mr Knauf’s lawyers confirmed he did not write the letter to Mr Markle and “it has never been his belief that he was an author”, Mr Mill said.

The court heard that his lawyers said: “Mr Knauf did not draft, and has never claimed to have drafted, any parts of the electronic draft or the letter and would never have asserted copyright over any of their content.

“In our client’s view, it was the duchess’s letter alone.”

Mr Mill added: “This unequivocal statement of Mr Knauf’s position also gives the lie to the defendant’s inferential case, in its defence to both the privacy and copyright claims, that the claimant considered using the letter ‘as part of a media strategy’.”

He said Meghan “shared a draft” of the letter with Harry and Mr Knauf “for support, as this was a deeply painful process that they had lived through with her”.

“Mr Knauf was responsible for keeping the senior members of the royal household apprised of any public-facing issues, the media spectacle surrounding Mr Markle being one such issue,” Mr Mill added.

He told the court that Mr Knauf “suggested that a reference to Mr Markle’s ill-health be included”, which Meghan did, but that “Mr Knauf did not suggest any specific wording”.

Mr Mill asked Lord Justice Warby to grant summary judgment in relation to the remaining parts of Meghan’s copyright claim, arguing that ANL’s case on the ownership of copyright in the letter “has been shown to be completely baseless”.

ANL does not oppose summary judgment being granted, but the publisher “does not consent to summary judgment because its appeal against summary judgment in the copyright claim remains live”, the court was told.

Andrew Caldecott QC, representing ANL, said in written submissions that it was “a matter of regret” that Mr Knauf’s lawyers had not said he was not an author of the letter before the summary judgment hearing in January.

When Mr Knauf’s lawyers told ANL that he was not a co-author, the publisher “swiftly recognised the impact of the information in that letter upon part of its copyright defence… and indicated that it would not oppose summary judgment”, Mr Caldecott said.

He also said it was “a matter for the court” whether it granted summary judgment on the rest of Meghan’s copyright claim, as “summary judgment has already been entered on the issue of copyright infringement”.

In the summary judgment ruling in February, Lord Justice Warby said ANL’s publication of Meghan’s letter to her father was “manifestly excessive and hence unlawful”.

He said: “It was, in short, a personal and private letter.

“The majority of what was published was about the claimant’s own behaviour, her feelings of anguish about her father’s behaviour, as she saw it, and the resulting rift between them.

“These are inherently private and personal matters.”

The judge said “the only tenable justification for any such interference was to correct some inaccuracies about the letter”, contained in an article in People magazine, published days before ANL’s five articles, which featured an interview with five friends of Meghan.

But Lord Justice Warby added: “The inescapable conclusion is that, save to the very limited extent I have identified, the disclosures made were not a necessary or proportionate means of serving that purpose.

“For the most part they did not serve that purpose at all.

“Taken as a whole, the disclosures were manifestly excessive and hence unlawful.”

He also said ANL’s arguments on ownership of the copyright of the letter “seem to me to occupy the shadowland between improbability and unreality”.

In March, the publisher was ordered to print a statement on the front page of the Mail On Sunday and a notice on page three of the paper stating it “infringed her copyright” by publishing parts of the letter to Mr Markle.

Lord Justice Warby later ruled that the statement did not have to be published “in the same position, and be in the same size font, as the front-page trailer complained of”.

But the front-page statement about Meghan’s victory in her copyright claim was put on hold, to allow ANL time to seek permission to appeal.

The hearing before Lord Justice Warby is expected to conclude on Wednesday afternoon.