The latest stage of phone-hacking claims featuring the publisher of the Daily Mirror and the Duke of Sussex is set to take place at the High Court.

In December, a judge ruled that phone hacking became “widespread and habitual” at Mirror Group Newspapers (MGN) titles in the late 1990s and was practised “even to some extent” during the Leveson Inquiry into press standards in 2011.

Mr Justice Fancourt also concluded that Harry’s phone was hacked “to a modest extent” by MGN, awarding him £140,600 in damages.

The duke, 39, said his partially successful case against MGN was “a great day for truth, as well as accountability” and called on the police to investigate the publisher of the Daily and Sunday Mirror and The People.

At a hearing last month, the High Court in London heard that the group of people who sued the publisher were seeking payment of £1,976,660 from MGN towards the legal costs of bringing “generic” allegations to court.

Mr Justice Fancourt is set to give his ruling on the costs on Friday.

David Sherborne, for the group, said decisions about the costs in Harry’s case against the publisher are reserved until the rest of his claim is determined.

Harry sued MGN for damages, claiming journalists at its publications were linked to methods including phone hacking, so-called “blagging” – gaining information by deception – and use of private investigators for unlawful activities.

There are a further 115 articles in his claim after a sample of 33 were examined at the trial last year, which saw Harry enter the witness box, with 15 articles found to have been the product of unlawful information gathering.

Roger Mallalieu KC, for MGN, told the court the publisher made offers to settle with Harry but the terms were confidential.

The barrister said in written submissions that the group suing the publisher had only seen “partial success on the trial issues” and those who lost their claims should pay their “respective share” of the so-called “generic” costs.

Harry’s case was heard alongside similar claims brought by actor Michael Turner, who is known professionally as Michael Le Vell and is most famous for playing Kevin Webster in Coronation Street, actress Nikki Sanderson and Fiona Wightman, the ex-wife of comedian Paul Whitehouse.

Claims brought by Ms Sanderson and Ms Wightman were dismissed by Mr Justice Fancourt because they were made too late, despite the judge finding that some of their complaints were proved.

Mr Justice Fancourt is set to hand down his ruling at a hearing in London at 10.30am on Friday.