Walter Bagehot famously wrote in The English Constitution (1867) that the British monarch has three rights: the rights to be consulted, to encourage and to warn.
It is worth quoting the relevant part of the book at length:
"To state the matter shortly, the sovereign has, under a constitutional monarchy such as ours, three rights — the right to be consulted, the right to encourage, the right to warn. And a king of great sense and sagacity would want no others. He would find that his having no others would enable him to use these with singular effect. He would say to his minister: “The responsibility of these measures is upon you. Whatever you think best must be done. Whatever you think best shall have my full and effectual support. But you will observe that for this reason and that reason what you propose to do is bad; for this reason and that reason what you do not propose is better. I do not oppose, it is my duty not to oppose; but observe that I warn.” Supposing the king to be right, and to have what kings often have, the gift of effectual expression, he could not help moving his minister. He might not always turn his course, but he would always trouble his mind.
In the course of a long reign a sagacious king would acquire an experience with which few ministers could contend. The king could say: “Have you referred to the transactions which happened during such and such an administration, I think about fourteen years ago? They afford an instructive example of the bad results which are sure to attend the policy which you propose. You did not at that time take so prominent a part in public life as you now do, and it is possible you do not fully remember all the events. I should recommend you to recur to them, and to discuss them with your older colleagues who took part in them. It is unwise to recommence a policy which so lately worked so ill.” The king would indeed have the advantage which a permanent under-secretary has over his superior the parliamentary secretary — that of having shared in the proceedings of the previous parliamentary secretaries. These proceedings were part of his own life; occupied the best of his thoughts, gave him perhaps anxiety, perhaps pleasure, were commenced in spite of his dissuasion, or were sanctioned by his approval. The parliamentary secretary vaguely remembers that something was done in the time of some of his predecessors, when he very likely did not know the least or care the least about that sort of public business. He has to begin by learning painfully and imperfectly what the permanent secretary knows by clear and instant memory. No doubt a parliamentary secretary always can, and sometimes does, silence his subordinate by the tacit might of his superior dignity. He says: “I do not think there is much in all that. Many errors were committed at the time you refer to which we need not now discuss.” A pompous man easily sweeps away the suggestions of those beneath him. But though a minister may so deal with his subordinate, he cannot so deal with his king. The social force of admitted superiority by which he overturned his under-secretary is now not with him, but against him. He has no longer to regard the deferential hints of an acknowledged inferior, but to answer the arguments of a superior to whom he has himself to be respectful. George III in fact knew the forms of public business as well or better than any statesman of his time. If, in addition to his capacity as a man of business and to his industry, he had possessed the higher faculties of a discerning statesman, his influence would have been despotic. The old Constitution of England undoubtedly gave a sort of power to the Crown which our present Constitution does not give. While a majority in parliament was principally purchased by royal patronage, the king was a party to the bargain either with his minister or without his minister. But even under our present constitution a monarch like George III, with high abilities, would possess the greatest influence....
It would be childish to suppose that a conference between a minister and his sovereign can ever be a conference of pure argument. “The divinity which doth hedge a king” may have less sanctity than it had, but it still has much sanctity. No one, or scarcely any one, can argue with a cabinet minister in his own room as well as he would argue with another man in another room. He cannot make his own points as well; he cannot unmake as well the points presented to him. A monarch’s room is worse.... He will not refute the bad arguments of the king as he will refute another man’s bad arguments. He will not state his own best argument effectively and incisively when he knows that the king would not like to hear them. In a nearly balanced argument the king must always have the better, and in politics many most important arguments are nearly balanced. Whenever there was much to be said for the king’s opinion it would have its full weight; whatever was said for the minister’s opinion; would only have a lessened and enfeebled weight."
To this day, Halsbury's Laws continues to recognise these rights:
"[The Queen] still has the right to be consulted, the right to encourage, and the right to warn. However, she also has the right to offer, on her own initiative, suggestions and advice to her ministers even when she is obliged in the last resort to accept the formal advice tendered to her."
