There will be a paper put before the Queen on Monday afternoon about the ‘Harry problem’ at the heart of her family.
The document has been prepared for her by her Private Secretary, Sir Edward Young, and the Keeper of the Privy Purse, Sir Michael Stevens, who is in charge of Royal Family finances.
JUST IN: Queen releases statement after Sandringham summit saying the family had "very constructive discussions" about plans for Harry and Meghan's future and it has been agreed “there will be a period of transition in which the Sussexes will spend time in Canada and the UK”. Read in full.
We don’t know how long the paper is, nor how many options are on it, but, given the complexities of the issues at state, it will consist of more than a few brief notes.
Prince Harry will attend the meeting at Sandringham and sit face-to-face with his grandmother for the first time since he and Meghan announced they wanted to quit the Royal Family and spend much of the year in Canada.
Prince Charles arrived at Sandringham on Sunday night straight from Oman where he had been on official duties following the death of the Sultan.
Prince William arrived for the family meeting from Anmer Hall, the home he and his family have on the Sandringham estate.
While all the senior Royals will be joined by their Private Secretaries, do not discount a moment when the Queen will kick everyone out of the room and they will meet just as a family.
There is no simple way to “quit” the Royal Family in the way Harry and Meghan have requested because it’s never been done before.
There is the issue of what kind of royal role he will do, how long he plans to reside outside the UK, what that means for tax purposes, does he keep his military titles, where will Archie be schooled, do they stay at Frogmore Cottage or fund their housing themselves?
The list is endless.
And it’s why one royal insider suggested it might be a little like the Brexit negotiations - long, complex and with a transition period before the exit can actually take place.
I suspect the Royal Family will be hoping this will be nothing like Brexit in terms of its duration.
I do know that various proposals have been bouncing around between the key family members and their various Private Secretaries all weekend - and even those exchanges have triggered tensions.
The negotiations did, however, need to start on Monday with some kind of idea of what the Sussexes want.
But unless they did that, they really could be here forever (which is a lot like Brexit).
Watch the latest episode of our series The Royal Rota: Royal Editor Chris Ship is at Sandringham on the global reaction to Harry and Meghan's decision to step away from the Family