THERE are many things we are yet to discover about Prince Charles's letters to government ministers, but given the missives have been dubbed the "black spider memos" it is probably safe to assume they were not written in green ink, the fabled choice of irate epistolists everywhere.

The rest is all to play for, however, following the Supreme Court's decision yesterday that the letters, which the Guardian has been fighting for 10 years to see, can be published. There are 27 of them, written to seven departments between 2004-2005. This was a period when Tony Blair was in Downing Street, the fallout from the invasion of Iraq was growing ever more intense, the new Scottish Parliament building was officially opened, the Hunting Act was passed, identity cards were being mooted and the Prime Minister said he would not seek another term after the next one even though no-one had yet asked him to (some things never change). It was all go, but what was Charles having a go about?

We shall find out within the 30 days, assuming the Government does not wield the redacting pen. Given how fiercely the Coalition has fought to keep the letters secret anything is possible (including a tightening of the rules in future). It has been three years since a tribunal ruled that the letters should be released under Freedom of Information laws. Dominic Grieve, the former Attorney General, then wielded a veto, arguing the letters contained the prince's "most deeply held personal views and beliefs". Legal move after move followed, leading eventually to yesterday's ruling.

In short, the present Government has spent a lot of your money fighting the publication of these letters. One might have thought the Coalition would be relaxed about the matter, given the letters were written to Labour ministers, but no-one circles the wagons faster than the British Establishment when it perceives itself to be under threat. After all, publishing the prince's letters is just not cricket, is it? That was roughly the view of David Cameron yesterday. This, said the Prime Minister, was about the principle that senior members of the royal family were able to express their views to government confidentially, adding: "I think most people would agree this is fair enough."

Dear oh dear, Dave. You clearly have been standing too close to the Aga if you think that "most people" would regard Prince Charles as having a divine right to lobby ministers on state matters and for that not to be seen as political interference at odds with the supposed neutrality of the monarchy. Just as the first rule of Fight Club is not to talk about Fight Club, so the first rule of Monarchy Club is that the head of state must remain politically neutral. "Her" government, or in the case of Charles "his" government, could hail from any part of the political spectrum. As long as a party can command a majority in the Commons it gets the job, without fear of, or favour to, the person on the throne.

Now, one might argue that Prince Charles, as second in line to the throne, is not the head of state and therefore should not be bound by such rules. But he will be one day, and if he is already in the habit of lobbying ministers there is nothing to stop him doing more of the same when he becomes king.

Then again, if it turns out that he was putting pen to paper in defence of good causes who are pesky journalists to interfere? Think of Prince Charles and his politics and sunlit images of the countryside, architecture, and biscuits (ever tried Duchy Originals? Well worth a second mortgage) hove into view. Where is the harm, really? Well, he may have been writing to ministers on such benign subjects as lemon snaps, or he might have been objecting to genetically modified crops. The point is we do not know for certain, and in a democracy we should.

If the prince chooses to make a stand on an issue to the point where he is lobbying an elected minister then he, and they, ought to be prepared to disclose that stand. To argue otherwise is to pretend that he is just another citizen when it is as plain as a monstrous carbuncle on his nose that he is not. The institution to which he belongs, and the position to which he aspires, is publicly funded in one way or another. Moreover, as a royal, he is able to exercise considerable influence should he choose. While he may not vote or stand for election he would be steering government policy, and doing so, moreover, behind closed doors, or within sealed envelopes. Ministers could ignore him, and chances are they were tempted to, but a thwarted prince is not a foe any ambitious minister would choose to have.

All of this should be plain to any democrat. Yet at heart, and a sinking one at that, that same democrat must surely accept that royal lobbying has gone on for centuries and will continue to do so. In that sense, Charles's only "sin" is to have been caught out putting pen to paper. Other royals make their views known in more subtle ways. Or maybe it was sheer coincidence that in the last days of the referendum campaign the Queen was heard to say that Scots should "think very carefully about the future". If one does not think that was a loaded statement, imagine the effect if she had said, "Scots should vote as they wish". Such is the power of the monarchy.

Then there is the weekly meeting between prime minister and monarch. What is this but a chance for the monarch to make their opinion clear? Or are we to believe that nothing more controversial than the weather is discussed at these meetings? We shall never know, of course. The closest any of us will get to being a fly on the wall is going to see The Audience, a play by Peter Morgan. Given no prime minister ever talks about what is discussed, fiction is all we have to go on. We will never be able to say with certainty what influence, if any, for good or for otherwise, has been brought to bear down the years. The entire operation, as with so much to do with the monarchy, is conducted behind a jewel-encrusted and firmly closed curtain. One could not imagine the American electorate, or the citizens of any other democracy worth the name, putting up with this.

The British state, of which Charles is a part, needs no encouragement to erect more protections around its privileges. At a time when we should be making government more open and accountable (not least to avoid the scandals of the past reoccurring), the idea that a prince's letters to ministers should be afforded special consideration and protection is absurd. And if the author of those letters is not happy he can always give up being a prince and apply for another job where he can make his robust views known. I hear there is a position going spare on Top Gear.