Prince Harry and Meghan face a fight to keep the Sussex Royal brand over fears they will exploit their Palace connections to rake in a billion dollar fortune.
Aides threatened to force them to change the name of their charitable foundation and social media profile amid concerns it may have negative effects for the Royal Family.
The humiliating move came after the couple were ordered to ditch their HRH titles and banned from carrying out official duties.
And as Harry, 35, prepared to leave the UK for Canada to join Meghan, 38, and their son Archie, a row broke out over who will pay for their £3million a year security bill.
The terms of their split from royal life were set out in another unprecedented statement from Buckingham Palace on Saturday after the couple struck a deal with the 93-year-old Queen, Prince Charles and Prince William.
An insider said: “It was made clear to Harry and Meghan that sacrifices would have to be made.
"The deal on the table was the only workable solution for the sake of the monarchy and when it came down to it, they wanted out at any cost so agreed to the terms in front of them.
“Now their Sussex Royal branding is causing a great deal of issues.
“They are obviously keen to keep it but as they are no longer working members of the royal family in any way or form, it seems they will have to give it up and rebrand themselves for their new working lives.”
Harry and Meghan registered the Sussex Royal name with intellectual property firm's and trademarked more than 100 items from books to stationary and T-shirts to bandanas.
Industry experts said their global stardom could launch them into the stratosphere of the corporate world.
Giants from Silicon Valley including Netflix and Apple as well as a host of US television networks are understood to be ready to table bids to work with Harry and Meghan on a range of projects.
Talent manager Jonathan Shalit tweeted: “Meghan and Harry will become a billion dollar brand.
“Fashion and consumer product ranges, endorsements and advertising. Books, TV and film (scripted and non-scripted), paid public appearances, company directorships in return for shares.”
Harry and Meghan, who have 10.8 million Instagram followers, had spoken of their wish to be part-time royals who wanted to “collaborate” with Her Majesty.
But after days of negotiations they were told there was “no halfway house agreement”.
An insider said: “You can’t be half in and half out.”
Palace sources suggested the deal represented a “compromise” from the duke and duchess to allow them to walk from The Firm.
Harry is understood to have offered to pay back the £2.4million of public funds used to renovate the couple’s Frogmore Cottage home as a way of brokering the deal.
The couple will be free to make millions from commercial deals without oversight from Buckingham Palace, although final arrangements are still to be agreed.
But as the Mirror exclusively revealed last week, any private contracts will take months to be agreed over fears their private ventures could sully the royal brand.
And in what will be a blow for Harry, he has to give up his military roles as Captain General of the Royal Marines, Commodore-in-Chief, Small Ships and Diving and Honorary Air Commandant at RAF Honiton.
A source said losing the titles will “deeply hurt” the prince, who served two tours in Afghanistan and is passionate in his support for the Armed Forces.
He will continue his work with the Invictus Games.
The Queen and Prince Charles were said to be saddened that Harry, Meghan and eight-month-old Archie will live in Canada.
It is not known when they will be back.
Charles has assured the couple he will still support them financially, after previously giving them £2.4million a year to fund their lifestyles.
Harry last night visited the Ivy Chelsea Garden restaurant in London for a private event in support of his charity Sentebale which helps children in Lesotho, Botswana and Malawi.