Prince Harry is suing the British press

Daniel Taylor, a lawyer whose office, Taylor Hampton, represents Ms Wightman, said it was extraordinary that the trial went ahead at all. It is only the second case to go to trial after dozens of cases and more than a decade of hacking-related litigation, he said, and it carries risks for both sides.

Harry, he said, “is likely to be subject to rigorous and lengthy cross-examination” by lawyers representing Mirror Group. That could be embarrassing given that the hacking took place in the years before Harry met his wife Meghan, when he was single and involved in sometimes turbulent relationships.

But the Mirror Group is also taking a risk by going to court, said Mr. Taylor, as defeat could encourage other hacking victims to come forward. “It is willing to do so because a victory or partial success in the process, in its view, will slow or halt the oncoming wave of claims filed against the company,” he said.

On Monday, Harry managed to annoy the judge, Timothy Fancourt, by not appearing at the trial as expected. Mr Sherborne explained that he had stayed in California on Sunday to celebrate his daughter, Lilibet’s second birthday, and would appear in court on Tuesday and Wednesday to testify. A lawyer for the Mirror Group expressed concern that he would not be given a day and a half for cross-examination.

Some royal observers said it was a sign of Harry’s polarizing reputation in Britain that pre-trial media coverage focused on whether testifying would diminish his status rather than the journalistic issues at stake.

“The core of what he’s trying to do is being watered down,” said Mr. Hunt, former BBC correspondent. “It’s almost like phone hacking was priced in,” he said, adding, “it wasn’t priced in if you were the victim.”