The judge has rejected the Duke's request for a preliminary trial to decide whether the Mail on Sunday story caused serious harm to his reputation, saying: “Ultimately this is an issue of fact.”

The Duke, who is suing the publishers of the Mail on Sunday over a report that he “tried to keep his legal fight with the government over police bodyguards a secret”, claimed the story harmed his reputation so as to “constitute an attack on his honesty and integrity and undermine his fitness to be involved both in charitable and philanthropic work in general”.

“I have refused to direct trial of the issue of serious harm,” he said. “I appreciate that the Claimant’s [Harry’s] case is one based (at this stage) solely upon inference, but ultimately this is an issue of fact.

“The Defendant [Associated Newspapers] must have an opportunity to advance any factual case in answer to the Claimant’s inferential case."