Britain’s Prince Harry has arrived at London’s High Court to attend a hearing in his claim against Associated Newspapers Limited over allegations of unlawful information gathering.

The Duke of Sussex last year joined a group of high-profile figures, including singer Elton John, in legal action against the publisher of the Daily Mail, the Mail on Sunday and the Mail Online.

The lawsuit accuses Associated Newspapers Limited (ANL) of engaging in various means of criminal activity to obtain information on high-profile figures over the years.

Elizabeth Hurley, Sadie Frost, David Furnish and Doreen Lawrence make up the rest of the plaintiffs behind the legal action.

They claim they were “victims of abhorrent criminal activity and gross breaches of privacy,” according to a statement from their representatives at the time.

The group has accused ANL of hiring private investigators to carry out unlawful acts such as planting listening devices in homes and cars and recording private calls. It also claims the publisher would pay corrupt police officials to obtain inside information, engaged in impersonation and deception to obtain medical records, and would hack into bank accounts and financial transactions by “illicit means and manipulation.”

When the lawsuit was brought in October, the publisher rejected the allegations as “preposterous smears” and labeled the suit a “pre-planned and orchestrated attempt to drag the Mail titles into the phone-hacking scandal,” according to Britain’s PA Media news agency.

An ANL spokesperson said at the time that the claims were “unsubstantiated and highly defamatory claims, based on no credible evidence,” PA reported.

Monday was the start of a four-day preliminary hearing at London’s Royal Courts of Justice, during which ANL is trying to have the case thrown out.

Elton John, Furnish’s husband, also made an appearance as court proceedings got underway.

Prince Harry was seen sitting “towards the back of the courtroom and occasionally taking notes in a small black notebook,” PA reported.

David Sherborne, a lawyer for the claimants, outlined the allegations against ANL, including illegally entering private property, unlawfully intercepting voicemail messages, listening to live calls and obtaining medical records, the news agency said.

“The claimants each claim that in different ways they were the victim of numerous unlawful acts carried out by the defendant, or by those acting on the instructions of its newspapers, The Daily Mail and The Mail On Sunday. They range through a period from 1993 to 2011, even continuing beyond until 2018,” he wrote in submissions to the court.

ANL’s lawyers argued in their own written submissions that the lawsuit was brought too late and should be dismissed without trial, according to PA.

One of ANL’s barristers, Adrian Beltrami, said in the submissions that each claimant needs to demonstrate that they did not know, or could not have discovered earlier, that they might have been able to bring a claim against ANL for alleged misuse of their private information.

“The claimants have failed to show that they have a real prospect of discharging their burden at trial and the court should not hesitate to dismiss these stale claims at an early stage, thereby avoiding what would otherwise be a considerable waste of time, costs and the court’s resources,” PA quoted Beltrami as saying.

The case against ANL is one of several lawsuits launched by Prince Harry in recent years.

He is also suing ANL after its Mail on Sunday newspaper published a story about his separate legal proceedings against the UK’s Home Office over his family’s security arrangements when visiting Britain.

Meanwhile, he also sued the owners of UK tabloid newspapers the Sun and the Daily Mirror in 2019 over alleged historical phone hacking. The case against the publisher of the Daily Mirror i  due to go to trial in May.

The 38-year-old royal’s surprise appearance in London on Monday is thought to be his first trip back to the United Kingdom since he and his wife, Meghan, attended the funeral of the late Queen Elizabeth II in September.

In the months since, the Sussexes have released a Netflix docu-series and the duke’s memoir, which have provided further insight into his fractured relationship with the rest of the royal family.

Harry is not expected to see his brother, the Prince of Wales, a royal source told CNN. As it is the school vacation, Prince William is not in Windsor, the source added.