Researchers have called for greater transparency from the Foreign Office over the files it holds on the Duke of York. Officials responding to freedom of information requests have given a variety of reasons why the files cannot be released.

Andrew Lownie, an author who is researching a biography of Prince Andrew, was told that the files could not be made public until 2065, and implied there was a general rule that papers relating to members of the royal family must remain closed until 105 years after their birth.

Last week, a spokesperson for the UK Information Commissioner’s Office said: “There’s nothing in the Freedom of Information Act about that”, adding that they were not aware of anything preventing the files’ release under any other legislation.

“The government’s covering up for Andrew,” said Lownie, who has described trying to get information on the prince from government departments as like “whack-a-mole” and has called for a register of royal interests.