The Duke of Sussex is expected to formally settle a High Court libel claim against the publisher of The Mail On Sunday and MailOnline over allegations he snubbed the Royal Marines after stepping down as a senior royal.

Harry sued Associated Newspapers over two articles published in October, which claimed he had “not been in touch … since his last appearance as an honorary Marine in March”, citing “informed sources”.

In documents filed with the High Court just before Christmas, the duke’s lawyers said Harry had been “personally affronted” by the articles which had “caused huge damage to his reputation”.

They also claimed that Harry’s ability to help veterans and serving military by attracting public support were “seriously” hampered by the allegations as they would “diminish his credibility in the eyes of (military) personnel”.

On December 27, The Mail On Sunday printed an apology, accepting the duke had been in touch with the Royal Marines, and said it had made a donation to the foundation managing the duke’s Invictus Games.

Mr Justice Nicklin is expected to hear details of the settlement of Harry’s claim against Associated Newspapers at a brief remote hearing on Monday.

When Harry, who served as an Army officer for 10 years, and wife Meghan stood down as working royals and moved to the US, his honorary military titles, including the prestigious post of Captain General of the Royal Marines, were put on hold.

He is not allowed to take any particular role using the titles at present, but they have not yet been handed to other members of the royal family.

They will be examined in March as part of the monarchy’s 12-month review of the Sussexes’ departure arrangements.

The Mail On Sunday article, published on October 25, claimed “exasperated top brass” were considering a replacement because Harry “has not been in touch by phone, letter nor email since his last appearance as an honorary Marine”.

It also alleged the duke had not responded to a personal letter from Lord Dannatt, a former head of the British Army, and quoted a retired senior officer who called on Harry to “take the job seriously”.

But Harry’s lawyers said in court documents that The Mail On Sunday and MailOnline “disregarded the claimant’s reputation in its eagerness to publish a barely researched and one-sided article in pursuit of the imperative to sell newspapers and attract readers to its website”.

They also said the duke was “frustrated and saddened” as the articles would diminish his credibility with veterans and serving military with mental health issues “and therefore make them less likely to seek the help being offered”.

They added: “The claimant reasonably fears that this will, in turn, have devastating effects upon such individuals, including leaving them more susceptible to suicide.”

The High Court hearing is due to begin at 10.30am on Monday.