However, it was said to be ultimately down to Queen Elizabeth that the idea of compromise was removed entirely.
The book stated: "By the end of the week, the five scenarios had been worked through. The view from the palace establishment was that, however much time Harry and Meghan spent away from royal duties, anything they did would reflect on the institution. That meant that the normal rules about royal behaviour would apply. They should not act or take decisions
in order to gain financial or other material benefits for themselves, their family, or their friends.
"But the Sussexes wanted their freedom: freedom to make money, freedom to dip their toes into American politics. There was no way for the two sides to reach an agreement on that point.
"Crucially, it was the Queen who took the view that unless the couple were prepared to abide by the restrictions that applied to working members of the royal family, they could not be allowed to carry out official duties."
One source said: "There was a very clear view: you can't be in and out. And if you've got such clarity of view, it's very difficult to say, 'Why don't we go 10 per cent this way instead of 20 per cent?' Compromise was off the table, removed by the Queen."
Despite the criticism Harry and Meghan - who have children Archie, three, and Lili, 15 months, together - have faced for their decision to start a new life in the US, one insider thinks it is the best thing that could have happened to the 38-year-old prince.
A source "who knows Harry well" but is "upset" about their move said: "There is a part of me that thinks Meghan did Harry the greatest kindness anyone could do to him, which was to take him out of the royal family, because he was just desperately unhappy in the last couple of years in his working life. We knew he was unhappy, but we didn't really know what the solution would be. She came along and found the solution."