The Duchess of Sussex will find out tomorrow whether she has succeeded in a bid to have parts of her privacy claim against a newspaper over its publication of a letter she wrote to her father resolved without a trial.

Meghan, 39, is suing the publisher of The Mail On Sunday and MailOnline over a series of articles which reproduced parts of the handwritten letter sent to 76-year-old Thomas Markle in August 2018.

She is seeking damages for alleged misuse of private information, copyright infringement and breach of the Data Protection Act over five articles, published in February 2019, which included extracts from the “private and confidential” letter to her father.

Her lawyers argue Associated Newspapers Limited (ANL) has “no prospect” of defending her claim for misuse of private information and alleged breach of copyright over the publication of the letter.

At a remote High Court hearing in January, Meghan’s lawyers asked Mr Justice Warby to grant “summary judgment” in relation to her privacy and copyright claims, a legal step which would see those parts of the case resolved without a trial.

The judge will deliver his ruling at 4pm on Thursday.

During the two-day hearing Justin Rushbrooke QC, representing the duchess, described the letter as “a heartfelt plea from an anguished daughter to her father”, which Meghan sent to Mr Markle “at his home in Mexico via a trusted contact … to reduce the risk of interception”.

He said the “contents and character of the letter were intrinsically private, personal and sensitive in nature” and that Meghan therefore “had a reasonable expectation of privacy in respect of the contents of the letter”.

In written argument, Mr Rushbrooke added: “It is as good an example as one could find of a letter that any person of ordinary sensibilities would not want to be disclosed to third parties, let alone in a mass media publication, in a sensational context and to serve the commercial purposes of the newspaper.”

The barrister argued that “there is no real prospect of the defendant establishing that the claimant had no reasonable expectation of privacy in relation to the contents of the letter and the defendant’s contentions to the contrary are utterly fanciful”.

Mr Rushbrooke continued that, even if ANL was justified in publishing parts of the letter to Mr Markle, “on any view the defendant published far more by way of extracts from the letter than could have been justified in the public interest”, saying the Mail’s “use of the letter was and is manifestly disproportionate”.

In relation to Meghan’s copyright claim, Ian Mill QC, also representing the duchess, argued that “she and she alone” created a draft of the letter to her father “which she then transcribed by hand”.

He argued the letter to Mr Markle was “an original literary work in which copyright subsists and is owned by the claimant” and asked the court to “grasp the nettle and decide the issue at this hearing”.

ANL claims Meghan wrote the letter “with a view to it being disclosed publicly at some future point” in order to “defend her against charges of being an uncaring or unloving daughter”, which she denies.

Antony White QC, representing ANL, said in written argument that the case was “wholly unsuitable for summary judgment”.

Mr White told the court last month there was “uncertainty as to a number of significant factual matters which can, and should, be investigated at trial when the court will have the full picture in terms of disclosure and evidence”.

He added: “This is particularly so when the claimant’s case in respect of certain important factual issues has shifted, (including) in relation to the circumstances in which the letter was written and the extent to which she had disclosed information about the letter with a view to publication.

“There are now on the record a number of inconsistent statements made by her that she will need to explain.”

Mr White argued that, if the court assessed whether Meghan had a reasonable expectation of privacy in relation to the letter, “it would be likely to come to the conclusion that the claimant has not shown a reasonable expectation of privacy” and that “on the contrary, she expected or intended its contents to enter the public domain”.

He said that a letter from lawyers representing four former employees of the Duke and Duchess of Sussex – dubbed the “Palace Four” – indicated they would be able to “shed some light” on the drafting of Meghan’s letter to her father.

He told the court it was also “likely” there was further evidence about whether Meghan “directly or indirectly provided private information” to the authors of an unauthorised biography of the Duke and Duchess of Sussex, Finding Freedom.

The full trial of the duchess’s claim was due to be heard at the High Court this month, but last year the case was adjourned until autumn 2021 for a “confidential” reason.