Prince Philip's will is a ninety-year secret to preserve the dignity of the Queen

Philip died in April at the age of 99, after more than seven decades of marrying the Queen.
Wills are usually public documents in Britain, but for nearly a century it has been the custom to enforce secrecy on the wills of senior members of the royal family by order of the Supreme Court.
Judge Andrew MacFarlane said Philip's will must be kept confidential for 90 years. After that, they can be opened in private considering whether they should be published.
As MacFarlane said in a written judgment, "I have thought that because of the constitutional position of the Queen, it is appropriate that we should have a private practice of royal wills. There is a need to strengthen the protections afforded to the truly private aspects of the lives of this limited group of individuals in order to preserve the dignity of the Queen and those close to her family.”
The judge stressed that he was neither seen nor informed of the contents of the will.