How extraordinary that so much effort, by so many royal advisors and politicians, should have been expended in keeping secret what a future head of state has written to government ministers.

All those who deplore the Supreme Court’s decision, however, are wrong.

For I believe this is a great day not only for the freedom of information which the law demands and allows.

It should also be seen as a great day for the monarchy.

The Supreme Court ruling that Prince Charles' 27 'black spider' memos should be released marks not only a great day for the freedom of information, but also one for the monarchy

One Tory bigwig recently told me that the Prince’s letters would reveal him to be ‘barking mad’, but when I questioned him, he admitted he had not read a word of them.

I thought this was a good example of how much damage the secrecy over his letters has done the Prince of Wales.

When we are told that his correspondence is so hush-hush that it must be suppressed, we naturally imagine his letters will be inflammatory, or embarrassingly eccentric. We remember some of the Prince’s strong turns of phrase, as when, in his leaked diaries, he described senior members of the Communist Chinese government as ‘appalling old waxworks’.

We remember, too, his tendency to self-pity and self-absorption, and the round-robin letter to friends in which he complained about being seated in club-class on a plane to China for the Hong Kong hand-over to the Beijing government in 1997, saying tetchily his seat was ‘uncomfortable’.

But despite this, many of his views are eminently sensible.

He is bursting with ideas on subjects as varied as the environment, architecture, town planning, Shakespeare, agriculture, the King James Bible and much else besides.

What’s more, his opinions on architectural carbuncles or on the need for caution over genetically modified food are shared by countless numbers of Britons.

Contrary to popular belief, the Queen has not always been completely above the political fray

For decades, he has been a sort of one-man Opposition to many of the idiotic or ugly things going on in our country.

Many commentators have said that they deplore the Prince sounding off and getting involved in the day-to-day running of this country’s affairs. They fear that if he expresses views, he will be seen as having a political bias.

This, they claim, could not be more different from the approach which has been so successfully pursued by the Queen – who is believed not to express opinions to individual ministers.

The monarchy is deemed to be strengthened by Her Majesty’s silence.

But the Queen has not always been completely above the political fray – and for all we know, she might have made any number of interventions and recommendations to ministers of which we know nothing.

How else, for instance, did we all come to be told the story that she deeply disagreed with Mrs Thatcher about the PM’s refusal to impose trade sanctions on South Africa during the apartheid years?

The Queen certainly had a vested interest – as she feared for the future of her Commonwealth and even lined up with her Commonwealth leaders against the British prime minister.

The story was impeccably sourced – to the Queen’s Press Secretary of the day, Michael Shea – yet it was denied by No. 10. The row over South Africa was undoubtedly an example of the monarch so-called ‘interfering’.

Anyway, the truth is that we no longer live in an age of deference. Nor do we live in an age of secrecy.

Yesterday’s judgment makes plain that Charles cannot hide the contents of the 27 letters to Labour ministers.

It is entirely right that letters which he writes to publicly elected representatives about matters of government policy should be made available to the public.

But ever since an amendment to the Freedom of Information Act in 2011, any such correspondence is legally deemed to be private.

Ever since an amendment to the Freedom of Information Act in 2011, any correspondence by the Royal Family is legally deemed to be private

Regardless, I would support to the utmost not only his right, but his duty to get involved in political issues – as long as he does not undermine his position or that of the monarchy.

But answer this question: would you rather have a king who spoke up for the silent majority against self-appointed experts on agriculture, architecture, defence, youth employment, education, Islam – or would you rather have an ignoramus? What is the point of his having established so much expertise in certain fields if he cannot share it with ministers?

The corollary of his ‘interference’ is that when he does speak up, he should be prepared to argue his position in public, rather than in spidery secret memos.