The Duke of Sussex and six other household names will have to stump up an initial £9.5million to the Daily Mail’s publisher for its legal fees over their failed unlawful information gathering claims.

A High Court judge issued the ruling on Friday after a slew of famous faces, including Baroness Doreen Lawrence and Sir Elton John, unsuccessfully sued Associated Newspapers Limited (ANL).

ANL strongly denied the claims which were heard at an 11-week trial in London earlier this year, with judge Mr Justice Nicklin dismissing all the cases in a judgment on July 7.

The cases returned to the High Court for a two-day hearing over costs, where the court was told ANL’s total costs were £34.5million.

On Friday, Mr Justice Nicklin gave his decision on the size of an initial payment the group will make to ANL, as well as how the full costs will be assessed.

The seven claimants, also including Sir Elton John and Liz Hurley, must pay an initial £9.54m by Friday of next week .

The court has ruled the Mail publisher can seek further costs meaning the famous names could eventually end up having to pay up to the £34.5million costs of the case for the Mail publisher.

They had insurance to cover up to £16.2m of ANL's costs in the event of losing the case - means the duke and others could face a bill of some £18m that will have to be paid from their personal wealth.

In his ruling, Mr Justice Nicklin said the claims brought against Associated Newspapers were “speculative and substantially inferential” and “lacked a proper evidential foundation”.

Associated Newspapers called the costs judgment ‘a devastating critique of an attempt to destroy a newspaper and the reputations of its journalists, editors and executives’.

The ruling comes after it was made public on Wednesday that Harry and his wife the Duchess of Sussex are moving back to the UK.

The couple decamped to California more than six years ago amid the Megxit crisis but now will relocate back from the US to the UK later this month to live in a non-royal residence outside London.

ANL, which also publishes the Mail On Sunday, had asked for more than £9.9 million as an interim payment ahead of future hearings to decide its legal costs in depth.

Lawyers for the group of household names, also including David Furnish, Sadie Frost, Liz Hurley and Sir Simon Hughes, argued the interim payment should be just over £7.9 million.

Mr Justice Nicklin ruled that Associated Newspapers should be awarded indemnity costs, finding the case went beyond simply being a hard-fought legal battle in which serious allegations failed.

He said the way the claims were brought, pursued and publicly presented took the litigation outside the “ordinary and reasonable conduct of civil proceedings”.

Mr Justice Nicklin said in his ruling that the group of household names undertook a “high-risk strategy” in their failed claims against Associated Newspapers Limited (ANL).

He said: “Allegations of the utmost seriousness were advanced before the evidential foundation for many of them had been established, and the case was then pleaded at the widest possible level to obtain disclosure and seek to substantiate the individual claims.”

He continued: “The existence of such litigation does not confer a licence to turn every subsequent claim against a newspaper publisher into a wide-ranging investigation of that publisher’s conduct over many years.”

The judge also said that the “dynamic” of the claim against ANL was “materially different” from those against other publishers.

He said: “In the absence of admissions by Associated, the claimants could not treat the fact that private information appeared in an article, or that there was no readily obvious lawful source for that information, as sufficient to bridge the evidential gap between suspicion and proof.”

In a statement following Mr Justice Nicklin’s ruling on Friday, a spokesperson for the publisher said the decision was “another overwhelming victory for the Mail and its journalism”.

They said: “His judgment is a devastating critique of an attempt to destroy a newspaper and the reputations of its journalists, editors and executives.

“From well before the trial started, the claimants’ lawyers knew that their main witness had denied making the preposterous allegations on which the claims were based.

“Despite this collapse in evidence to support the extremely serious allegations of ‘abhorrent criminal activity, crimes and terrible and reprehensible covert acts’ by the Mail, they were emblazoned in a lurid press release issued on behalf of Baroness Lawrence, Prince Harry and the other claimants, with the exception of Sir Simon Hughes. The allegations were not withdrawn, and were pursued until the bitter end of the trial.

“This placed a huge burden on the Mail to defend the reputations of its innocent journalists and the paper itself.

“The truth is that these outrageous claims should never have been brought. That they were pursued raises disturbing questions about the conduct of elements of the legal profession.”

Former MP Sir Simon Hughes said he was disappointed by the judge’s ruling on the legal costs, adding he was “taking the time necessary to consider both the substantive and the costs judgment and whether to pursue appeals against decisions in either judgment or both.”

David Bailey-Vella, chairman of the Association of Costs Lawyers, said that the High Court ruling ordering the Duke of Sussex and six other household names to pay more than £9.5 million to Associated Newspapers Limited “could not have gone much worse” for the group.

He said: “An award of costs on the indemnity basis disapplies the court-approved costs budget, which is vital for Associated as it spent much more than it said it would, and removes the requirement that the costs must be ‘proportionate’. They must still meet the test of being reasonably incurred and reasonable in amount, however.

“The only chink of light is the judge’s comments about the £34m costs claim appearing ‘excessive’ and his ‘real concerns’ about how much of it would meet that test before a costs judge.

“Though they failed to obtain a cap of £18-20m on the amount Associated could recover to bring it in line with the cover provided by their legal expenses insurance, the claimants will surely try again before the costs judges to try and show they relied on Associated’s original budget when buying the insurance and so should not have to pay more.”

Mr Bailey-Vella also said the process “will not be quick” unless there is a settlement.

He said: “Serious allegations, especially those carrying reputational weight, must be advanced with proper foundation and maintained responsibly. (The ruling) also makes clear that parties cannot distance themselves from the conduct of their legal teams or experts when that conduct drives unnecessary cost.

“For costs lawyers, the message is unmistakable: disciplined case management and evidential rigour are now central to avoiding indemnity costs exposure in high-stakes litigation.”