Prince Harry said the thought of Piers Morgan having had access to and listening to Princess Diana's private messages made him "physically sick" during his testimony in London's High Court in his legal case against Mirror Group Newspapers.

The Duke of Sussex—who shared he was emotionally scarred by British tabloids as a child—is suing for damages from the British tabloid publisher. Mirror Group publishes over 240 regional papers including The Daily Mirror, Sunday Mirror and Sunday People.

The Prince made history by becoming the first senior Royal to take the witness box in 130 years.

In the trial covering 33 stories published between 1995 and 2011, the Royal claimed journalists from those publishing titles obtained information through illegal tactics like phone-hacking, deception and using private investigators for unlawful activities.

“I would say their actions affected every area of my life,” Harry wrote in his witness statement.

He shared the trauma stemming from the articles he believed originated from the hacking.

According to the Prince the stories adversely affected his personal relationships.

“It created a huge amount of paranoia in my relationships."

"I would become immediately suspicious of anyone that was named in a story about me."

"I felt that I couldn’t trust anybody, which was an awful feeling for me especially at such a young age.”

Also in his statement, Harry took aim at Piers Morgan.

Morgan was the editor for The Daily Mirror between 1995 and 2004–a period which included the time Harry's mother, Diana the Princess of Wales, was killed in a vehicular collision in Paris in 1997.

In the trial, Harry's lawyer David Sherborne presented letters to the court that Diana had written to English actor Morgan Barrymore about a "secret meeting" as claiming that as a child, Harry was impacted by the unlawful information-gathering techniques used by the press.

Sherborne mentioned that Morgan said he "heard rumors" of meetings between Diana and Barrymore, which the British presenter mentioned in his 2005 book The Insider.

Sherborne claimed the reason why Morgan may have heard about those meetings was because The Daily Mirror journalists would have listened to “private messages."

Harry said in his witness statement:

“The thought of Piers Morgan and his band of journalists earwigging into my mother’s private and sensitive messages … makes me feel physically sick and even more determined to hold those responsible, including Mr. Morgan, accountable for their vile and entirely unjustified behavior."

In an interview with the BBC, Morgan–who previously called the Netflix trailer for the Harry & Meghan docuseries "vomit-inducing"–denied knowing of any phone-hacking incidents at The Daily Mirror.

He also said their methods were “completely wrong” and it was “lazy journalists being lazy.”

Twitter enjoyed watching Morgan trying to keep his cool while in the hot seat.

The Duke of Sussex also pointed to evidence disclosed by the Mirror Group Newspapers that its papers had made 289 payments to private investigators to gather information on him and his associates.

Harry wrote:

“I understand from my solicitors [that these] are huge numbers in the context of this litigation, especially considering that the defendant is known to have concealed and destroyed evidence of their wrongdoing on an industrial scale."

“I now realize that my acute paranoia of being constantly under surveillance was not misplaced after all.”

The Prince is also suing Murdoch’s News Group Newspapers, publisher of The Sun, and Associated Newspapers Limited–which owns Daily Mail, TheMail on Sunday, Metro, i newspaper, and New Scientist–for similar claims of phone hacking and other unlawful tactics to get information and invade Harry's privacy.