The King has asked the Duke and Duchess of Sussex to move out of Frogmore Cottage for good to allow Prince Andrew to move in, The Telegraph understands.
Talks between Buckingham Palace and the couple are understood to have been going on for some time, but have picked up pace recently.
A friend of the Sussex's suggested the decision to move them out of Frogmore has not been welcomed by the couple, noting that “they made that place their home”.
They are understood to view the cottage as “the only place left that's safe” for them and their children in the UK, not least given the ongoing row between Prince Harry and the Home Office over its decision to withdraw his security detail.
It comes as the Duke of York had feared he would be forced out of the Royal Lodge by King Charles, who is on a drive to slim down spending.
The Duke is set to have his £249,000 annual allowance cut from April, and has told friends that this will leave him unable to maintain the 98-acre Windsor property.
However, the King does not intend to leave his brother "homeless or penniless," a Royal source told The Telegraph, suggesting that alternative arrangements have been made for his accommodation.
Frogmore cottage is much smaller than Royal Lodge, a 30-room mansion at Windsor Great Park which has been the Duke's home since 2003.
The Duke and Duchess of Sussex lost their taxpayer-funded police protection in the aftermath of quitting as senior working royals. In July, Prince Harry won the right to challenge a Home Office decision not to grant him automatic police protection whenever he is in the UK.
The Duke, 37, argued that he inherited a risk at birth and that as such, he, his wife Meghan and their children Archie, two, and Lilibet, one, should be afforded permanent protective security in the UK, regardless of their status as non-working royals.
In asking for a judicial review, he said he had been denied a “clear and full explanation” of the composition of the Executive Committee for the Protection of Royalty and Public Figures, otherwise known as Ravec, and others involved in the decision to rescind his security status.
Ravec said at the time that the Sussexes’ plan to live abroad as private citizens did not “fit readily” into any category of its framework.
However, it recognised that the Duke occupied a “particular and unusual position” and that he may need protection in certain circumstances, to be considered on a case by case basis.
The Sussex' spokeswoman could not be reached for comment.