Prince Harry's lawyer said the British tabloids sowed mistrust between Harry and Prince William going back 20 years

• Prince Harry and William's strained relationship was mentioned at the phone hacking trial.
• Harry is suing Mirror Group Newspapers as he alleges journalists hacked his voicemail in the '90s.

Prince Harry and Prince William's fractured relationship was brought up in the UK's High Court on Monday during the phone hacking trial between Prince Harry and the Mirror Group Newspapers, The Telegraph reports.

Harry is suing Mirror Group Newspapers over unlawful information gathering, alleging that journalists from several publications hacked his and other celebrities' voicemails in the 1990s and early 2000s and published the information they discovered.

Lawyers for Mirror Group Newspapers said that it "unreservedly apologizes" to the prince for one instance of unlawful information gathering in 2004 and accepts Prince Harry was entitled to "appropriate compensation," The Telegraph's India McTaggart reported on Tuesday. Mirror Group Newspapers denies the other allegations.

The prince arrived at London's High Court on Tuesday to provide a witness statement. But before the royal's arrival, Harry's barrister David Sherborne told the court on Monday that a story written by one of Mirror Group Newspapers' publications may have resulted in "mistrust" between the brothers.

In 2003, The People — a Mirror Group Newspapers publication — reported that Harry and William had a dispute over whether to meet with Princess Diana's former butler, Paul Burrel, who they had publicly accused of betraying her, according to The Telegraph.

A source told the publication that the brothers were at "loggerheads" during Harry's year abroad, The Telegraph added.

"Even at this very early formative stage the seeds of discord between these two brothers are starting to be sown," Sherborne said, according to The Telegraph.

"Brothers can sometimes disagree but once it is made public in this way and their inside feelings revealed in the way that they are, trust begins to be eroded. One can see how the mistrust can set in from an early age, exactly because of this type of activity," he added.

Harry wrote about his strained relationship with William in his memoir, "Spare," which was released in January. In the book, Harry detailed disagreements they had over his relationship with Meghan Markle, and said that his brother's press office traded stories about him and Meghan.

The brothers have made only a handful of public appearances together in recent years, including the funerals of the Queen and Prince Philip and most recently, King Charles' coronation ceremony in May.

In a witness statement issued to the court on Tuesday, Harry spoke about the negative impact the British press has had on his life. He said that when he was in his 20s, paparazzi were "everywhere I went," and that the tabloids' coverage meant he had to face "judgments and opinions" from people regardless of whether the stories were true or not, The Guardian's Jim Waterson reports.

"Where historical wrongdoing has taken place, we have made admissions, take full responsibility and apologise unreservedly, but we will vigorously defend against allegations of wrongdoing where our journalists acted lawfully," a spokesperson for Reach Plc, publisher of Mirror News Group titles, said in a statement sent to Insider on Tuesday.

"MGN is now part of a very different company. We are committed to acting with integrity and our objective in this trial is to allow both the business and our journalists to move forward from events that took place many years ago," the statement added.

Harry is also suing News Group Newspapers as he alleges that journalists from The Sun newspaper obtained information through phone hacking. The company has denied any wrongdoing, according to a separate story by The Guardian.

Representatives for the Duke of Sussex, Prince William, and Reach Plc, owner of Mirror Group Newspapers, did not immediately respond to Insider's request for comment.