Prince Harry claims the royal family withheld information about phone hacking from him to avoid opening "a can of worms".
The Duke of Sussex made the allegation about his family, which he refers to as "the Institution", in submissions for a privacy claim he filed with other celebrities against the publisher of the Daily Mail, Associated Newspapers (ANL).
Lawyers for the group, which includes pop superstar Elton John, claim ANL commissioned the breaking and entry into private property, illegally intercepted voicemail messages and obtained medical records.
The alleged wrongdoing dates from 1993 to 2011, but some went on as late as 2018, according to the group's lawyer, David Sherborne.
In his partially redacted statement, the duke said he "became aware that I had a claim that I could bring" only in 2018.
"The Institution was without a doubt withholding information from me for a long time about ... phone hacking," he added.
"That has only become clear in recent years as I have pursued my own claim with different legal advice and representation."
The prince went on to say: "The Institution made it clear that we did not need to know anything about phone hacking and it was made clear to me that the royal family did not sit in the witness box because that could open up a can of worms."
The prince, who lives in California, made a surprise appearance at London's High Court on the first two of four days of hearings this week, on Monday alongside John and other people involved.
On Tuesday, Prince Harry told the court that his former girlfriend Chelsy Davy endured the terrifying experience of photographers swarming over their holiday destination after the Mail on Sunday published its location.
The duke explained in detail how his former partner felt she was “being hunted” and that he was “scared” she would end the relationship after the newspaper allegedly used “unlawful” methods to discover their holiday in Argentina.
Associated Newspapers, publisher of the Mail on Sunday and Daily Mail, is bringing a bid to end High Court claims by celebrities including Prince Harry, Sir Elton John and Baroness Doreen Lawrence over allegations of unlawful information gathering.
The accusations include hiring private investigators to secretly place listening devices in cars and homes.
The duke has quoted 14 newspaper articles published in the Mail on Sunday and Daily Mail featuring information known only to his trusted circle, that he claims were the product of unlawful information gathering by the publications.
“This intrusion was terrifying for Chelsy," Prince Harry said of their holiday.
"It made her feel like she was being hunted and the press had caught her, and it was terrifying for me too because there was nothing I could do to stop it and now she was in my world.
“She was shaken and I was really paranoid about trying to protect our privacy, as the article says. Their behaviour and treatment of Chelsy was not normal.
“I was scared that Chelsy was going to run in the opposite direction or be chased and harassed to death.”
Prince Harry also claimed that the monarchy was “withholding information” from him about the phone-hacking scandal.
He said the institution made it clear to him that the royal family did not need to know about the issue that rocked the British press industry, and “did not sit in the witness box because that could open up a can of worms”.
“The institution was without a doubt withholding information from me for a long time about NGN’s [News Group Newspapers] phone hacking and that has only become clear in recent years as I have pursued my own claim with different legal advice and representation."
The duke said that during his 10 years as an army officer from 2005, he was “extremely busy and worked long hours”, and did not have the time to regularly read newspapers or watch television.
He said he had no knowledge that his phone had been hacked.
“My understanding was that a voicemail my brother had left for me had been accessed and published," Prince Harry said.
"Aside from that, I thought that the hacking had been confined to the phones of members of staff.
Prince Harry and Meghan Duchess of Sussex through the years - in pictures
"I do, however, remember [former Daily Mail editor] Paul Dacre clearly stating that phone hacking had not taken place at Associated.
"I have no real recollection or knowledge of the phone hacking trials from before 2016.”
He said it was only after he had brought legal proceedings against other publishers that he learnt from his solicitors “that some private investigators had come forward to admit — for the first time — to unlawful information gathering that had been commissioned by Associated".
Prince Harry said he was told one private investigator “regularly commissioned” by the Mail on Sunday had used landline tapping, voicemail hacking, blagging, and obtaining credit card bills and phone records to “unlawfully obtain” his private information.
He was astounded by the fact a hardwire tap had been placed on the phone of his close friend Guy Pelly.
The duke claims in his witness statement that a Mail on Sunday article about a fledgling relationship with Laura Gerard-Leigh ended prematurely after her family were visited by the press.
“Laura and I had a very brief but private relationship which lasted for a matter of months. The fact that ANL journalists learnt so quickly was therefore extraordinary," he said.
“This article is a prime example of why my relationship with Laura did not last long. It led to Laura’s parents being door-stepped. which they were understandably not pleased about."
Prince Harry concludes his statement by saying: “Unfair is not a big enough word to describe the fact that Associated is trying at this early stage to prevent me from bringing my claim.
“I do not see why Associated should get away with something they have covered up and lied about for however many years.
“I simply do not understand how I could have discovered that I had these claims against Associated for the unlawful acts I am claiming about any earlier than I did, especially as current senior figures at Associated lied all those years ago, which everyone believed.”
A spokesperson for ANL said that Prince Harry "has become a serial litigant against Mail newspapers with whom he seems obsessed".