The Duke of Sussex is one of seven high-profile people, including Sir Elton John and Baroness Lawrence of Clarendon, who has brought legal action against Associated Newspapers Limited (ANL).
Others who have brought allegations against the publisher include David Furnish, Sadie Frost, Liz Hurley and Sir Simon Hughes.
They are accusing the paper of carrying out or commissioning unlawful information gathering, which ANL “firmly” denies.
Allegations include the hiring of private investigators to place listening devices inside people’s homes and cars, dishonestly obtaining medical and financial information and accessing and listening into phone conversations.
In his ruling on Friday, Mr Justice Nicklin said ANL “has not been able to deliver a ‘knockout blow’ to the claims of any of these claimants”.
He continued: “Fair resolution of any limitation defence ... must await trial.”
In his 95-page-judgment, he said that each of the seven people in the claim have a “real prospect” of demonstrating that ANL concealed “relevant facts” that would have allowed them to bring a claim against the publisher earlier.
In a statement, the seven individuals bringing claims said they were “delighted” by the decision, and said: “We intend to uncover the truth at trial and hold those responsible at Associated Newspapers fully accountable.”
Speaking to The Independent on the financial implications of the case heading to trial, expert privacy lawyer Philippa Dempster said: “The larger reported damages awards in phone hacking claims dating back to 2015 were around £200k upwards.
“With seven claimants in the current cases, that could amount to around £1.5m in damages alone.
“The costs of both sides are likely to exceed this sum if the case goes to trial. So the final bill for Associated Newspapers in damages and costs, if the claims succeed, could be easily in the region of £4m-£5m.
“This could encourage others who believe they have similar claims against newspapers based upon stories that go back beyond the six-year limitation period, to bring privacy actions.”
During a court hearing in March, the duke made a surprise appearance at the Royal Courts of Justice, where his lawyer David Sherborne argued that those bringing legal action were “thrown off the scent”, having believed “categorical denials” from ANL.
In her witness statement, Baroness Doreen Lawrence, the mother of murdered Stephen Lawrence, had said she felt “played for a fool” by the Daily Mail, believing them to be “the good people, not the bad”.
Associated Newspapers has strongly denied the allegations, with Adrian Beltrami KC arguing that the high-profile individuals could have used “reasonable diligence” to discover if they had a potential claim before October 2016.
The lawyer said the legal action against it has “no real prospects of succeeding” and is “barred” under a legal period of limitation.
At a preliminary hearing, the publisher asked a judge to rule in its favour without a trial, arguing the legal challenges against it were brought “far too late”.
However, Mr Justice Nicklin ruled the claims can proceed, paving the way for a further court hearing at a later date.
The decision that the case can go to a full trial was welcomed by actor Hugh Grant, the director of the Hacked Off group, which campaigns for press reforms.
“This ruling is a significant blow to the Daily Mail and great news for anyone who wants the truth about allegations of illegal press practices to come out,” he said.
The case is one of six legal battles Harry has brought since leaving the royal family, with his civil litigation also including a legal challenge against the Home Office regarding the provision of his personal security.
Alongside actor Hugh Grant, he is suing NGN, the publisher of The Sun and the now-defunct News of the World, over unlawful information gathering, as well as seeking damages from MGN, the publisher of the Daily Mirror, the Sunday Mirror and the Sunday People.
Prince Harry had also brought two cases against the Home Office over security arrangements for himself and his family when they were in the UK. This follows a February 2020 decision which stated he would no longer be given the “same degree” of personal protective security when visiting.
He is also suing ANL over a February 2022 Mail on Sunday article about his legal fight with the Home Office.