A judge ruled that the prince and other plaintiffs could not expand their claims of unlawful actions by News Group Newspapers in the U.K. to include allegations regarding Rupert Murdoch.

Prince Harry was dealt a setback in his long-running legal campaign against Britain’s tabloids on Tuesday after a high court rejected a bid to draw Rupert Murdoch into allegations about how Mr. Murdoch’s London papers dug up personal details about him and later concealed or destroyed evidence of it.

Justice Timothy Fancourt ruled that lawyers for Harry and about 40 other plaintiffs could not amend their complaint against News Group Newspapers, publisher of The Sun, to include Mr. Murdoch, the 93-year-old media mogul who controls the company, as well as other senior News Group executives.

“There is a desire on the part of those running the litigation on the claimants’ side to shoot at ‘trophy’ targets, whether those are political issues or high-profile individuals,” Justice Fancourt declared in the 284-page ruling. “This cannot become an end in itself. It only matters to the court so far as it is material and proportionate to the resolution of the individual causes of action.”

Prince Harry entering court last year. The case, which is scheduled to go to trial in January, will mark one of the final chapters of a sprawling litigation that flowed out of a phone-hacking scandal.Credit…Hannah Mckay/Reuters