LONDON — Prince Andrew, the second son of Queen Elizabeth II, has been forced to relinquish his military titles and royal charities, Buckingham Palace said on Thursday, a stinging rebuke by the British royal family a day after a federal judge in New York allowed a sexual abuse case against him to go ahead.

The palace said that Andrew, 61, who has been accused by Virginia Giuffre of raping her while she was a teenager, would also no longer use the title “His Royal Highness,” a prized symbol of his status as a senior member of the royal family. In a terse statement, the palace said that Andrew would “continue not to undertake any public duties” and that he “is defending this case as a private citizen.”

Andrew, who is also known as the Duke of York, has denied Ms. Giuffre’s allegations, which date from a period in which he was friendly with the financier and convicted sex predator Jeffrey Epstein. The duke’s lawyers tried to get her lawsuit dismissed, but the judge, Lewis A. Kaplan, ruled against him on Wednesday.

The decision by Buckingham Palace completes a stunning fall from grace for a man who was once one of the royal family’s most popular members — a dashing war hero and eligible bachelor — but who has since become a disgraced figure, left to explain why he associated with a convicted criminal like Mr. Epstein.

The announcement by Buckingham Palace came after extensive discussions within the royal family, according to people with ties to the palace. It was designed to head off an effort by Andrew to rehabilitate himself, according to one person. The language in Buckingham Palace’s statement, officials said, was meant to underscore the permanence of the sanction against him.

Andrew had been largely banished from public life since November 2019, when he gave a disastrous interview to the BBC in which he insisted he had never met Ms. Giuffre and made several bizarre claims to deflect her charges, among them that he was medically incapable of sweating, as she had asserted.

But the prince, who served as a helicopter pilot in the Falklands War, continued to hold several honorary military titles, some of which he had inherited from his late father, Prince Philip. That aroused protests from veterans of those units, who said it was unseemly to be under the command of someone with such charges hanging over him.

The decision to deprive Andrew of his military titles and the honorific “His Royal Highness” puts him on the same footing as his nephew, Prince Harry, who was forced to give up both after he and his wife, Meghan, withdrew from royal duties and moved to Southern California in 2020.

But it could weaken Andrew’s standing as he fights the charges, since he will no longer have the weight of the crown behind him.

A palace official said that all of the duke’s roles had been turned back to the queen and would be redistributed to other members of the royal family. The official said the duke’s honors would not be returned to him.

The definitive nature of Buckingham Palace’s announcement seemed calculated to put as much distance as possible between the queen and any potentially lurid disclosures that could come in depositions of the prince, Ms. Giuffre or other witnesses if the case goes to trial.

In his ruling on Andrew’s motion to dismiss the case, the judge recapitulated the allegations in Ms. Giuffre’s lawsuit. In one, which occurred during a visit to Mr. Epstein’s house in Manhattan, she said she was forced by Ghislaine Maxwell, a friend of Mr. Epstein and the prince, “to sit on Prince Andrew’s lap, as Prince Andrew touched her.”

Ms. Maxwell was convicted last month of five of six criminal charges against her, including sex trafficking. Mr. Epstein, 66, was found hanged in a Manhattan jail cell in 2019 while awaiting a sex-trafficking trial. His death was ruled a suicide. Andrew has not been charged with a crime and figured only tangentially in Ms. Maxwell’s trial.

While the prince has already largely vanished from public view, his military affiliations were a lingering source of tension at a time when the royal family had hoped to showcase the queen’s 70 years on the throne.

More than 150 Royal Navy, R.A.F. and Army veterans signed a letter to the queen, asking her to strip Andrew of his eight British military appointments, which include colonel-in-chief of the Royal Irish Regiment, royal colonel of the Royal Regiment of Scotland, and colonel of the Grenadier Guards.

Julian Perreira, a former sergeant in the Grenadier Guards who served in Afghanistan, told The Times of London recently that Andrew “must step down immediately.”

“Being allowed to retain his role as colonel of the Grenadier Guards and other military titles, Prince Andrew will put a stain on the regiment’s proud history and will devalue the hard work of past and future generations of Grenadiers,” Mr. Perreira wrote.

Andrew’s reputation, critics say, has not been helped by his legal maneuvering. Rather than confronting Ms. Giuffre’s allegations directly, the prince scrambled to avoid being served with legal papers in Britain. His lawyers have tried to get the case dismissed on jurisdictional grounds and, most recently, on the basis of a 2009 settlement between Ms. Giuffre and Mr. Epstein.

In that agreement, Mr. Epstein paid Ms. Giuffre $500,000 to settle a lawsuit in which she had accused Mr. Epstein of sexually abusing her when she was a teenager, according to the deal, which was unsealed this month.

Under the terms of that agreement, Ms. Giuffre had released Mr. Epstein and other “potential defendants” from further litigation, a category that lawyers for the duke argued included him. In rejecting Andrew’s argument, Judge Kaplan did not address the merits of Ms. Giuffre’s claims.

Royal watchers said that the prospect of a lengthy trial would cast a shadow over the queen’s Platinum Jubilee year, which kicked off informally earlier this week when Buckingham Palace announced a nationwide competition to create the best recipe for a “platinum pudding.”