Like every Sandhurst cadet, the young Prince Harry had the age-old maxim – variously attributed to Erwin Rommel, the Duke of Wellington and the 6th century BC Chinese general Sun Tzu – drummed in to him throughout his military training: time spent in reconnaissance is seldom wasted.
So how is it that, after all those months of supposedly careful planning, the great "Sussex Royal" adventure now looks more like the retreat from Dunkirk?
And why, given their evident concern about retaining their royal status, have the Duke and Duchess of Sussex shown such disrespect for the person from whom that status descends, the Queen?
For the latest pique-filled statement on the sussexroyal.com website is enough to test the patience of the most sympathetic observers.
Yes, it must be extremely irksome to spend a great deal of time and money creating a new brand for yourself and registering a plethora of trademarks, only to be told that it's all a non-starter. Yes, the Sussexes may well feel there is one set of rules for those still inside the royal compound and another for them.
Yet the couple have only themselves to blame, not that they seem willing to acknowledge that. In the latest online message to their 11.2 million followers, they have posted a number of thinly veiled grumbles about various members of the Royal Family.
However, it is the dismissive tone of their remarks about the Queen's authority which surprises me most and leaves me wondering just who on earth is advising them.
The thrust of their argument is as follows: We are royal and we can jolly well use the word "royal" all over the world if we want to because it is not in the gift of the Queen or the British Government; we have merely chosen not to do so.
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Last Tuesday, the Mail's Rebecca English broke the story that the Palace had told Harry and Meghan their "Sussex Royal" brand would have to go because they are no longer part of regular royal operations. Alongside it, I wrote a piece explaining that there was nothing personal about this.
Rather, the monarchy's own "brand" is protected by a series of well-established laws including the Trade Marks Act, the Companies Act and an international agreement dating back more than a century and signed by 177 nations.
I also said the couple should have consulted the official royal website. "There," I wrote, "they will find exhaustive guidance from the Lord Chamberlain's Office on how businesses can lay claim to any sort of 'royal' status."
Late on Friday, the Sussexes put out a lengthy statement, following Palace confirmation of the Mail's story. It contained a number of peevish assertions but the standout gripe was this: "While there is not any jurisdiction by The Monarchy or Cabinet Office over the use of the word 'Royal' overseas, The Duke and Duchess of Sussex do not intend to use 'Sussex Royal' or any iteration of the word 'Royal' in any territory (either within the UK or otherwise) when the transition occurs Spring 2020."
What an extraordinary thing to say. Ever since they sprang their royal resignation on the Royal Family and the world, the Sussexes have said they plan to divide their time between the UK and abroad. They are not emigrating in perpetuity. So they could hardly raise two fingers to British law and set up some bogus "royal" entity internationally while expecting to be taken seriously back home.
Nor is this statement correct anyway. The monarchy in tandem with several "overseas" governments – including that in Canada where the couple are actually living – do have a jurisdiction over the word "royal". That is because the Queen is sovereign of 15 nations other than this one. Any requests for "royal" designation in Canada, for example, must be sent to the Governor-General's Office at – wait for it – 1 Sussex Drive, Ottawa.
The statement also neglects the fact that there is another player in this saga, namely the Secretary of State for Business, currently Alok Sharma, who has jurisdiction over "royal" names for "any type of business" under the Companies Act of 2006. Similarly, all royal trademarks fall under the Paris Convention for the Protection of Industrial Property of 1883.
Yesterday, I consulted a top commercial lawyer at an international law firm with offices in the UK and US. Her verdict: "Signatories to the Paris Convention are required to use reasonable efforts to enforce the trademark legislation of other signatory nation states, giving overseas effect to national protective laws. For example, the US signed the convention back in 1887 and Canada in 1923, so the UK could take steps to challenge the use of 'Sussex Royal' on websites and branding there."
Setting aside the legalities, it is the confrontational tone which jars. Whoever is behind this combative approach clearly has a tin ear for public sensibilities about the monarchy in the UK.
But then the couple are clearly not being advised from the UK. Just look at the phrasing of their statement: "Per the agreement" instead of "As per the agreement". Or "...when the transition occurs Spring 2020." Prince Harry would never write or talk like that. He would say "…when the transition occurs in the Spring of 2020".
The couple also complain that "while there is precedent for other titled members of the Royal Family to seek employment outside of [sic] the institution, for The Duke and Duchess of Sussex, a 12-month review period has been put in place".
It is not the rogue "of" that is likely to upset the Queen but the fact that the "12-month review period" is anything but a heavy-handed restriction on the Sussexes' freedom.
Rather, it is the monarch's way of ensuring the doors remain open for the couple to return if things do not go as planned. And right now, they certainly do not.