The High Court heard on Thursday this was possible due to unlawful activity by the publisher of the now-defunct News Of The World newspaper - with Meghan also targeted.

Harry is suing News Group Newspapers (NGN) over "a number of unlawful acts" he says were carried out by its publications, The Sun and the News Of The World, spanning three decades.

The company denies the allegations and a trial is scheduled for January next year.

The Duke of Sussex's team has previously told the court NGN unlawfully gathered information from 1996 to 2011, including details of interactions with his family and former partner, Chelsy Davy.

But in court documents for a hearing on Thursday, lawyer David Sherborne said several further Sun and News Of The World articles dating from 1994 to 2016 showed evidence of unlawful activity.

Harry's team has applied to add the new information to the duke's legal challenge.

Some of these articles came from NGN unlawfully intercepting calls of Diana, Princess of Wales, and Charles when he was the Prince of Wales and his now-wife Camilla, it was claimed.

Mr Sherborne said one article - which he claims was the result of unlawful activity and was published when the duke was 10 - had "information relating to his welfare… relationship with his mother… and her state of mind".

The activity was said to be "known about", "encouraged" and "concealed" by those in power at NGN, including former News Of The World editor Piers Morgan.

'Meghan targeted'

It allegedly continued until 2016, when two articles were published about Harry and Meghan at the start of their relationship.

"What is said is that in 2016, the defendant instructed one of its regular private investigators in the US," Mr Sherborne said in court.

"What we say he did was obtain private information in the form of a report… about the Duke of Sussex's then-new girlfriend, Meghan Markle, in order to obtain new information about their relationship, for the purpose of publication in The Sun."

The report allegedly included the duchess's mobile number and social security number, which was unlawfully obtained "in the full knowledge" of NGN.

New details to case

Mr Justice Fancourt previously told Harry he can't pursue claims of phone hacking by NGN, but could continue his wider case concerning unlawful information gathering.

But Mr Sherborne said evidence of phone hacking is "plainly probative" of unlawful information gathering by other means.

Barristers for NGN have previously told the court the new information is "designed to grab headlines" and that updating the case is "wholly unnecessary".

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Anthony Hudson KC, representing the publisher, said the duke's updated case was "wholly different in nature to the claims currently made".

He added: "NGN would have to engage in extensive investigations of entirely new allegations concerning new time periods and different individuals, journalists, information, alleged acts, forms of wrongdoing and/or causes of actions."

A spokesperson for NGN said that the updated claims were a "scurrilous and cynical attack" on current and former staff which should be "viewed with considerable caution".

Mr Justice Fancourt is expected to rule on whether new information can be included at a later date, following the conclusion of the hearing on Friday.