Meghan, the Duchess of Sussex, on Thursday won a lawsuit against a British media company that published parts of a letter she wrote to her estranged father, Thomas Markle, without the case having to go to a full trial.

The written ruling, published by the High Court in London, came after Meghan sued Associated Newspapers — the publisher of the Mail on Sunday and MailOnline — over five articles published in February 2019, which reproduced parts of the handwritten letter she sent after her wedding to Queen Elizabeth II's grandson Prince Harry in May 2018.

Judge Mark Warby ruled the articles did breach her privacy. Meghan "had a reasonable expectation that the contents of the Letter would remain private," his ruling said, adding that the articles "interfered with that reasonable expectation."

"Taken as a whole the disclosures were manifestly excessive and hence unlawful," he added. "There is no prospect that a different judgment would be reached after a trial."

However, he said issues relating to her copyright of the letter would need to be settled at a trial.

Speculation about Thomas Markle's attendance at the wedding dominated the build-up to the ceremony. He was expected to walk his daughter down the aisle, although he eventually missed the event due to ill-health.

In written submissions to the court, Meghan's legal team contended that printing the letter constituted a "triple-barreled" assault on "her private life, her family life and her correspondence."

A spokesman for Associated Newspapers said the company was "very surprised" by the ruling and "disappointed at being denied the chance to have all the evidence heard and tested in open court at a full trial."

He added: "We are carefully considering the judgment’s contents and will decide in due course whether to lodge an appeal."

The company had claimed the articles, two of which appeared in the Mail on Sunday and three on MailOnline, allowed Thomas Markle to respond to comments made by Meghan's anonymous friends in interviews given to People magazine.

In its written defense, the company said the duchess was willing for private matters to become public if it suited her and that she had expected or intended the letter to become public. It also argued for the paper's rights to freedom of expression.

Legal documents submitted by Associated Newspapers to the court in January 2020 also suggested that it would use evidence provided by Thomas Markle to back up its case. On the same day, the Daily Mail newspaper, which is also owned by Associated Newspapers, claimed on its front page that he was "set to be a star witness" in the case and "was prepared to give evidence against his own daughter."

Meghan has said that any money she wins will be donated to an anti-bullying charity.

During the initial hearings, it emerged in court documents that Meghan felt "unprotected by the institution" of Britain's royal family while in the press spotlight during her pregnancy with her son, Archie. Court filings also showed text messages sent by Harry in the days before his wedding, pleading with his now father-in-law to stop engaging with the media.

The couple stunned the public when they announced early last year they would "step back" from royal duties and begin paying their own bills.

Now based in California, they have begun a number of enterprises including hosting a podcast and in September signed a deal with Netflix to produce films, shows and documentaries.

They have also launched their charitable foundation, Archewell.