A U.S. private investigator known for decades in British tabloid circles has told the High Court that he carried out unlawful surveillance linked to coverage of Prince Harry, escalating a landmark lawsuit that challenges the practices of one of the U.K.'s most powerful newspaper groups. The testimony, delivered by 79-year-old Dan Portley-Hanks-known professionally as "Detective Danno"-adds a dramatic turn to claims that the press used illegal methods to obtain private information about public figures.

Portley-Hanks said he was an "independent supplier of data" who worked for Associated Newspapers Limited over many years, describing the company as his most lucrative client. In a witness submission, he acknowledged wrongdoing while conceding gaps in his recollection. "I know that I did unlawful stuff on him, but I cannot recall what exactly," he said, referring to the Duke of Sussex.

The admission lands as the High Court hears a consolidated action brought by Prince Harry and other prominent claimants against the publisher of the Daily Mail and Mail on Sunday. The lawsuit alleges a pattern of unlawful information gathering stretching from the early 1990s through the 2010s, including deception, misuse of private databases, and surveillance.

Portley-Hanks told the court he became adept at extracting sensitive details from minimal identifiers, earning a reputation as "the database guy." He said the work was so profitable that the newspapers dominated his client list. He also recalled obtaining contact information for Elton John and his partner, David Furnish, during the period in question.

The claims are contested. Representing the publisher, Antony White KC said Associated Newspapers "strongly denied" that Prince Harry was ever the subject of unlawful surveillance. The defense has highlighted what it characterizes as inconsistencies in the investigator's account, including disputed timelines over when alleged confessions were shared with claimants.

Associated Newspapers has also rejected allegations from other figures named in the case, calling them "entirely baseless" and "groundless." Addressing broader accusations of corruption, White told the court that "no document has been produced capable of supporting the allegation," according to court submissions.

The trial, before Justice Nicklin, features a roster of high-profile claimants alongside Prince Harry, including Elton John and Baroness Doreen Lawrence. They argue the case exposes systemic failures in newsroom oversight and accountability during a period of intense competition for scoops.