Meghan Markle, the Duchess of Sussex, has won a court battle to keep the names of five of her friends private for the time being as part of her legal action against a British tabloid that she says invaded her privacy.

But the victory also came with a stinging rebuke from the judge, who slammed the “tit-for-tat” High Court battle and the “eagerness” of both sides to play out the dispute in public.

Meghan, wife of the Queen’s grandson Prince Harry, is suing Associated Newspapers over articles in the Mail on Sunday that included parts of a handwritten letter she had sent to her estranged father, Thomas Markle, in August 2018.

As part of its defence, the paper argues that it published the letter in February 2019 after five of Meghan’s friends gave anonymous interviews to the US magazine People.

The duchess argues that she did not authorise her friends to speak to People and that the Mail on Sunday only wanted to name them to exploit the legal dispute for commercial reasons. She says naming them would pose a threat to their “emotional and mental wellbeing”.

On Wednesday (British time), Judge Mark Warby ruled at London’s High Court that their names could not be published for the moment, but that this could change.

“I have concluded that for the time being at least the court should grant the claimant the orders she seeks, the effect of which will be to confer protection on the sources’ identities,” he said.

But Judge Warby said it was “tolerably clear” that neither side had been willing to confine presentation of the case to the courtroom.

“Both sides have demonstrated an eagerness to play out the merits of their dispute in public, outside the courtroom, and primarily in media reports,” he said.

In court documents, Judge Warby said was evidence that the Duchess’ side had been “energetically briefing” the media throughout the case.

He also had words for the lawyers for the newspaper, saying they had not proved their claim that the Sussexes motivation for suing was “to afford them an opportunity to wage their own campaign against the press”.

Prince Harry and Meghan in one of their last appearances as senior royals in London in March.

The anonymity issue is one of several preliminary matters, with the full trial not expected until 2021. Judge Warby said the case had already taken 10 months and was still “some way from trial”, saying it needed to proceed more quickly.

“The duchess felt it was necessary to take this step to try to protect her friends – as any of us would – and we’re glad this was clear,” said a source close to Meghan, speaking on condition of anonymity.

“We are happy that the judge has agreed to protect these five individuals.”

Meghan and Harry live in Los Angeles with their toddler son Archie, having stepped down from their royal roles at the end of March.

Increasingly hostile relations between the royal couple and some British newspapers they accused of intrusive, inaccurate and sometimes racist coverage was one of the reasons they gave for leaving Britain for the US.

-with AAP