ANGELA LEVIN: Does Charles and Andrew's battle have roots in a plot to replace ... trends now

There are understandable reasons why King Charles might want his younger brother to move out of 30-room Royal Lodge, the Queen Mother's former home on the Windsor estate.

There’s the need to reduce expenditure, for example. 

The King has correctly identified the cost of the monarchy as a major political issue  and a potentially dangerous one – which is why he has cut the £250,000 annual grant that Andrew received from their late mother every year.

Is it appropriate for a disgraced prince to live in quite such style? Not everyone would think so. His children are grown-up, moreover, so it's not as if Andrew needs the space.

And then there is the question of where Prince William, heir to the throne, should be living with his young family.

For the moment, the Waleses are at nearby Adelaide Cottage, but few doubt that Royal Lodge is a more appropriate home for the future King. 

Yet I believe there are other, still more personal, reasons that might be colouring Charles’s determination to move his younger brother out of Royal Lodge. Reasons that are rooted in their own family history - and are perhaps related to one extraordinary episode in particular.

The first point is that their mother, the late Queen had a soft spot for Prince Andrew, her second son, and found it difficult to say ‘no’ to him.

Prince Philip, meanwhile, was proud of Andrew’s macho demeanour and delighted that he followed him into the Navy.

Perhaps it’s not surprising, then, that Andrew became rather bumptious, or that the personality differences between the two princes led to comparisons which were not always favourable to Charles.

For all the love that existed between Prince Philip and his thoughtful eldest son, it is also thought that the Duke of Edinburgh found Charles to be something of a puzzle.

Charles and Andrew are very different people and it is worth remembering that fact when it comes to the continuing row about the future of £30m Royal Lodge.

While Charles wants Andrew to downsize to the nearby five-bedroom Frogmore Cottage - which is no longer in use by Harry and Meghan - it would be wholly understandable if the younger man felt there were a personal dimension to the demand.