Senior government officials privately believed that the practice of keeping secret the wills of the royal family was legally questionable and even warned ministers not to discuss it in parliament, according to official documents. Over the past century, high court judges have issued secret legal orders allowing the wills of 33 members of the royal family to be kept confidential after hearings that were held behind closed doors. The secret orders have meant that these members of the royal family have been exempted from normal practice whereby the wills of British people are generally open to be inspected. On Monday, the Guardian reported that the secrecy allowed the Windsor family to prevent the public seeing how assets worth £187m at today’s prices, which are outlined in the wills, had been distributed. There has been little official explanation from the judiciary, government or royal family about why these secret orders, some of which concerned distant relatives of the Windsors, were justified. Official papers discovered in the National Archives show that during private discussions within government, a Whitehall official said in 1970 that the legal basis for granting these orders was “rather slender”. Another official described the practice as “somewhat haphazard”. Other documents show that in 1981, ministers were advised not to draw the attention of parliamentarians to the practice of keeping secret the royal wills while a key piece of legislation was being debated in the House of Lords. Officials advised ministers “not to read out” in parliament part of a document that noted the “customary” practice of closing the Windsors’ wills. On Wednesday, a court of appeal case will focus attention on the long-running practice. The Guardian is challenging a judicial decision to exclude the media from the secret hearing that led to a ruling last year to close Prince Philip’s will. As with all the other royal wills, a judge decided to close Philip’s will after a confidential application by lawyers for the Windsors. The media were not told about the hearing and were consequently prevented from attending or making submissions in favour of transparency. Philip’s will was the latest to be kept secret in a series of rulings dating back to 1911. The rulings are contentious, since wills drawn up by Britons are usually made public after they die. The purpose of this general right is to ensure that assets detailed in wills are properly distributed and not exploited by fraudsters. Legislation from the 19th century stipulates that the monarch’s will is kept secret. However, no equivalent law has been passed by parliament to prevent the publication of wills belonging to other members of the Windsor family. ‘Not to be read out’ in parliament The documents in the National Archives reveal official discussions behind closed doors about the legal justification for the secrecy surrounding what was described by a leading judge as “a special practice”. In October 1970, a senior Whitehall official, Hume Boggis-Rolfe, told Quintin Hogg, the then lord chancellor: “I have been able to find no authority whatever for the sealing-up of royal wills, apart from the rather slender authority” of a clause in a 1925 act. This he described as “the law in so far as there is any”. This clause stated that in general, wills were to be opened “subject to the control of the high court”, meaning that judges could seal wills if lawyers representing a dead person made an application. It did not define in what circumstances wills could be closed, nor did it refer specifically to the royal family. In his reply, Hogg agreed that this clause was the “sole” legal basis for concealing the royal wills. In June 1970, an unidentified Whitehall official queried whether the practice “is valid at all (a matter which may well be questioned one day)”. A senior official overseeing the probate system summarised how the wills of even distant members of the royal family had been kept secret. He admitted: “The practice of sealing up wills has been somewhat haphazard.” In the same month, the royal family consulted the government about whether a junior royal’s will could be sealed. A Whitehall official recorded that the proposal had been dropped: “The Buckingham Palace lawyers consider that except in special circumstances (for example, a will containing something that should not be made public) ‘fringe’ members of the royal family need not have their wills sealed. This should only be for HRHs [Royal Highnesses].” In the 1981 Senior Courts Act, the government renewed the clause that gave the public the general right to inspect wills, reiterating that this right could be curtailed by high court judges. Official briefing documents advised ministers on what to say when this act was being debated in the House of Lords. In passages marked “not to be read out” to parliament, the documents described how it was “customary” for judges to keep secret the wills of the royal family. Noting that wills drawn up by members of the public would usually be open, a civil servant wrote: “The point is of particular significance in relation to royal wills which in practice are frequently sealed up on the order” of a senior judge. The civil servant added: “The question of whether the ‘control of the high court’ may in law be exercised to render a will unavailable for inspection remains unanswered”. An official note written in 2002 shows that in private, government ministers and the judiciary have struggled to define which members of the Windsor family should be permitted to have their wills secret, and whether this should accorded, for example, to just the monarch’s consort and offspring, and not obscure relatives. The government declined to comment as the legal case brought by the Guardian was being heard. A Buckingham Palace spokesperson said: “The treatment of wills is a matter for the executors of estates.”