Prince Philip's will is going to stay private for the foreseeable future. 

The Duke of Edinburgh died on April 9, 2021 at age 99, and the UK's High Court has ruled the contents of his legal will are to be sealed for at least 90 years. 

The court's decision was quickly challenged by media giant The Guardian based on the premise that members of the media were not present at the hearing and the claim that the judge acted unfairly. 

BBC News reported the outlet's argument was that there was a "lack of external scrutiny". However, The Guardian reported today that the Court of Appeal ruled the judge acted correctly when he decided to hold a secret court hearing in which he banned the public from inspecting the late duke's will. 

Sir Geoffrey Vos, Dame Victoria Sharp and Lady Justice King, the three judges on the case, claimed "exceptional" circumstances were considered in the decision for the duke's will to stay private. 

"The two critically important things to protect were … the public interest in a) protecting the dignity, and b) protecting the private rights of the sovereign and close members of her family," the judges concluded. 

"The hearing was at a hugely sensitive time for the sovereign and her family, and those interests would not have been protected if there had been protracted hearings reported in the press rather than a single occasion on which full reasons for what had been decided were published." 

The decision follows High Court judge Sir Andrew McFarlane's ruling in September last year which stated the royal family were entitled to an enhanced level of privacy as a means "to protect the dignity and standing of the public role of the sovereign and other close members of her family". 

When Prince Philip died in April at the age of 99 he and Queen Elizabeth II had been married for more than seven decades. Photo / Getty Images 

The ruling continued to state any applications to see the wills unsealed would only be valid after 90 years and any applications submitted before that time limit would be "highly likely to fail in the absence of a specific, individual or private justification relating to the administration of the deceased's estate". 

"In short," High Court judge McFarlane added, "the publication of the list is intended to be an end in itself, in order to achieve transparency, and nothing more." 

At the time of the ruling, McFarlane also revealed that the late duke's will - stored inside a secret London safe - was under the Royal Courts of Justice's care. 

The top-secret safe also includes the wills of 32 senior members of the royal family dating back to Prince Francis of Teck in 1911 and includes the final wishes of Queen Elizabeth's mother, her sister, Princess Margaret and her uncle, King Edward VIII. 

"I am now custodian of a safe in which there are over 30 envelopes, each of which purports to contain the sealed will of a deceased member of the royal family," he said. 

"I can confirm that the earliest such envelope is labelled as containing the will of Prince Francis of Teck." He added, "The most recent additions were made in 2002 and are, respectively, the wills of Her late Majesty Queen Elizabeth, The Queen Mother and Her late Royal Highness Princess Margaret, Countess of Snowdon."