The Duke of Sussex claims he was “largely deprived” of important parts of his teenage years due to the unlawful actions of the Daily Mail’s publisher, court documents have shown as he made a surprise appearance at the High Court in London.

Harry, Sir Elton John, his husband David Furnish, Baroness Doreen Lawrence of Clarendon and Sadie Frost all attended the Royal Courts of Justice on Monday for the start of the first hearing in their claims against Associated Newspapers Limited (ANL).

The high-profile individuals are part of a group, which also includes Liz Hurley and former Lib Dem MP Sir Simon Hughes, bringing privacy claims against the publisher over allegations it carried out or commissioned illegal or unlawful information-gathering.

This included the hiring of private investigators to place listening devices inside cars, the “blagging” of private records and the accessing and recording of private phone conversations.

Lawyers for ANL, which is also the publisher of The Mail On Sunday and MailOnline, said the allegations are “firmly denied” and that the “stale” claims have been brought too late as it made a bid to throw out the cases.

During the first day of the four-day hearing in London, documents detailing the group’s claims were made available to journalists.

In a document filed on Harry’s behalf, barrister David Sherborne said the duke is “troubled that, through Associated’s unlawful acts, he was largely deprived of important aspects of his teenage years”.

The barrister continued: “In particular, suspicion and paranoia was caused by Associated’s publication of the unlawful articles: friends were lost or cut off as a result and everyone became a ‘suspect’ since he was misled by the way that the articles were written into believing that those close to him were the source of this information being provided to Associated’s newspapers.”

He added: “The claimant regards Associated’s unlawful acts to amount to a major betrayal given promises made by the media to improve its conduct following the tragic and untimely death of his mother, Princess Diana, in 1997.”

In documents detailing Baroness Lawrence’s claim, the court was told that the campaigner “wonders whether trusting the Daily Mail as she did caused her to have delayed or have failed her murdered son”.

The Labour peer is the mother of Stephen Lawrence, an aspiring architect who was stabbed to death by a group of up to six white youths in a racist attack as he waited at a bus stop in Eltham, south-east London, in 1993.

The Daily Mail, under then-editor Paul Dacre, campaigned to bring Mr Lawrence’s killers to justice.

In court documents, Mr Sherborne said Baroness Lawrence felt “anger, shock and upset” about allegedly being targeted by the paper.

Mr Sherborne said the Labour peer “never once suspected Associated” of the allegations due to her trust in the paper but that she “now sees that the Daily Mail’s true interests were about self-promotion and using her and her son’s murder as a means to generate ‘exclusive’ headlines, sell newspapers, and to profit”.

The barrister later said the alleged targeting included the illegal interception of her voicemails and the monitoring of her bank accounts as well as “corrupt payments to serving Metropolitan Police Service police officers, including on the Stephen Lawrence murder investigations, for confidential information”.

Other allegations disclosed for the first time on Monday included claims that Sir Elton and Mr Furnish’s landline at their home in Windsor was tapped.

Mr Sherborne said: “They are also mortified to consider all their conversations, some of which were very personal indeed, were tapped, taped, packaged and consumed as a commercial product for journalists and unknown others to pick over, regardless of whether or not they were published.”

The court also heard that Sir Elton and his husband Mr Furnish had not seen a copy of their first child’s birth certificate before it was unlawfully obtained by ANL.

He added: “They were heartbroken by the derogatory headline that Associated attached to it, clearly calculated to profit and generate public sensation about an event that they had so carefully guarded to keep precious.”

ANL’s lawyers have said the claims should be dismissed without a trial.

Adrian Beltrami KC, in written submissions, argued the legal actions have been brought too late and that the claims were “largely inferential”.

The barrister said the individuals have to prove they did not know earlier, or could not have discovered earlier, they might have had a claim against ANL for alleged misuse of their private information.

“Those claims, which relate to matters said to have taken place as early as 1993, and for the most part in the first decade of this century, are undeniably prima facie time-barred,” he said.

He later said none of the group said they believe they continued to be targeted by unlawful information gathering after 2015, adding: “In fact, in most instances their own case is that such targeting ended substantially before then.”

Mr Beltrami added that more than a decade after the Leveson Inquiry and several criminal and civil proceedings over phone hacking, “it would be surprising indeed for any reasonably informed member of the public, let alone a figure in the public eye, to have been unaware of these matters”.

He continued: “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.”

The barrister has also argued that unless lawyers for the people bringing the claim make an application, some aspects of the cases should be thrown out as they breach orders made by Lord Justice Leveson as part of the inquiry bearing his name.

Following Monday’s hearing, an ANL spokesman said private investigator Gavin Burrows allegedly confessing “to carrying out a wide range of criminal activities on behalf of Mail newspapers” had prompted the claims but “according to written submissions by Adrian Beltrami KC, counsel for Associated, Mr Burrows ‘has provided a signed witness statement denying that he was commissioned or instructed by Associated to carry out any unlawful activity’.”

The statement continued: “While the Mail’s admiration for Baroness Lawrence remains undimmed, we are profoundly saddened that she has been persuaded to bring this case.

“The Mail remains hugely proud of its pivotal role in campaigning for justice for Stephen Lawrence. Its famous ‘Murderers’ front page triggered the Macpherson report.

“Associated Newspapers, which owns the Daily Mail and Mail on Sunday, vigorously denies all the claims against it.”

The hearing before Mr Justice Nicklin in London will resume on Tuesday at 10.30am.