Prince Harry and six other household names are suing the publishers of the Daily Mail newspaper over alleged unlawful information gathering dating back 30 years.
The case has been ongoing since 2022 and is just one of several Harry has filed against media organisations since 2019 over alleged breaches of privacy, unlawful practices and false stories.
Associated Newspapers (ANL) - which also publishes The Mail on Sunday and MailOnline - strongly denies any wrongdoing.
A full trial is not expected to start at London's High Court until January, but a pre-trial hearing, which helps manage the case and resolve any outstanding issues, is set to take place today.
Here is everything you need to know about the case.
What's alleged?
The alleged unlawful acts are said to have taken place from 1993 to 2011, including the publisher hiring private investigators to secretly place listening devices inside cars and homes and paying police officials for inside information.
When bringing the lawsuit in 2022, lawyers for the claimants said they had become aware of "highly distressing" evidence revealing they had been victims of "abhorrent criminal activity" and "gross breaches of privacy" by Associated Newspapers.
Associated Newspapers denies the allegations, describing them as "preposterous smears", and claims the legal action is "a fishing expedition by [the] claimants and their lawyers".
The accusations include:
• The hiring of private investigators to secretly place listening devices inside people's cars and homes;
• The commissioning of individuals to surreptitiously listen into and record people's live, private telephone calls while they were taking place;
• The payment of police officials, with corrupt links to private investigators, for inside, sensitive information;
• The impersonation of individuals to obtain medical information from private hospitals, clinics, and treatment centres by deception;
• The accessing of bank accounts, credit histories and financial transactions through illicit means and manipulation.
Who else is involved?
While Prince Harry is one of the key players, as a group litigation, he is not the only claimant.
The others include:
• Actress Elizabeth Hurley
• Actress Sadie Frost
• Sir Elton John and his husband, filmmaker David Furnish
• Baroness Doreen Lawrence, mother of Stephen Lawrence
• Former Liberal Democrat politician Sir Simon Hughes
They all allege they have been victims of "abhorrent criminal activity" and "gross breaches of privacy" by ANL.
David Sherborne is the lawyer representing all the claimants.
What happened in 2023?
During a preliminary hearing in March 2023, Judge Matthew Nicklin was tasked with ruling whether the case can proceed to trial.
ANL had asked for the case to be struck out entirely, arguing the legal challenges against it were brought "far too late", but David Sherborne called for the publisher's application to be dismissed.
Lawyers for the publishers said the claims fell outside the statute of limitations - a law indicating that privacy claims should be brought with six years - and the claimants should have known, or could have found out, they had a potential case before October 2016.
They also argued some aspects of the cases should be thrown out as they breach orders made by Lord Justice Leveson as part of his 2011 inquiry into media standards.
During the hearing, a number of the claimants attended the High Court, including Prince Harry, to the surprise of the British media.
Witness statements from all seven claimants were also released. The duke's statement said he is bringing the claim "because I love my country" and remains "deeply concerned" by the "unchecked power, influence and criminality" of the publisher.
"If the most influential newspaper company can successfully evade justice, then in my opinion the whole country is doomed," he said.
On 10 November 2023, Mr Justice Nicklin gave the go-ahead for the case to go to trial, saying ANL had "not been able to deliver a 'knockout blow' to the claims of any of these claimants".
What's happened since?
Earlier this year, lawyers for the claimants sought to amend their case to add a swathe of new allegations for the trial.
They argued that they should be allowed to rely on evidence that they said showed the Mail was involved in targeting Kate, the Princess of Wales.
However, Mr Justice Nicklin ruled this allegation was brought too late before trial.
In a further development in November, the High Court heard that a key witness in the case, private investigator Gavin Burrows, claimed his signature on a statement confirming alleged hacking had taken place, was forged.
In the statement from 2021, Mr Burrows allegedly claimed to have hacked voicemails, tapped landlines, and accessed financial and medical information at the request of a journalist at the Mail On Sunday.
The statement was important, as five of the seven claimants involved in the case told the court they embarked on legal action against ANL based on evidence apparently obtained by Mr Burrows.
Mr Burrows previously retracted his statement in 2023, but the court heard he reiterated the denial to ANL's lawyers in September this year.
It is now up to the claimant's lawyer Mr Sherborne to decide if he still wants to call Mr Burrows as a witness for the trial.
Mr Justice Nicklin previously said if Mr Burrows gave evidence that was inconsistent with the evidence they had obtained, then he could apply to treat him as "hostile".
Could the case end before going to trial?
In short, yes.
During pre-trial reviews, cases can either be settled or dismissed from court in both civil and criminal cases, meaning no trial will take place.
This happened in Harry's case against News Group Newspapers (NGN), which publishes The Sun. The duke made similar accusations about NGN, which involved unlawful information gathering by journalists and private investigators.
Before an up-to 10-week trial began earlier this year, it was announced both sides had "reached an agreement" and that NGN had offered an apology to Harry and would pay "substantial damages".
The settlement was reported to be worth more than £10m, mostly in legal fees.
Another of Harry's legal cases, this time against Mirror Group Newspapers (MGN) over accusations of historical phone hacking, did go to trial.
The trial saw Harry take to the witness box, making him the first senior royal to give evidence in a courtroom since the 19th century.
In December 2023, the Honourable Mr Justice Fancourt concluded that the duke's phone had been hacked "to a modest extent" between 2003 and 2009, and 15 of 33 articles he complained about were the product of unlawful techniques.
He was awarded £140,600 in damages. During a further hearing in February 2024 a settlement was reached between Harry and MGN over the remaining parts of his claim.
If the ANL trial does go ahead early next year, it is unknown if Harry will travel to London to attend.
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