"I suspect the royal family would carry British public opinion still - perhaps only just - but its international standing is a key part of its value to the British state. If that were to be tarnished,it could be very damaging indeed."

The warning is simple:if the palace frustrates the pair's plan to leave,make their own money and move to Canada,then expect all hell to break loose. What they might have to share would apparently be enough to seriously damage the royal family at home and abroad. There is speculation that possible interview revelations could include allegations of sexism and racism practised by some members of the royal family or their senior staff.

There is no evidence Harry and Meghan asked for that threat to be conveyed publicly but there is little doubt Bradby is intimately familiar with their thinking and planning.

And they are obviously hurt and aggravated.

It seems the couple wanted to meet other family members to discuss their plans to split from the institution before it was announced,but were instead encouraged to write their thoughts down and submit them for further discussion. When they did just that,the plans leaked.

Bradby reports Harry and Meghan apparently find some family members"jealous and,at times,unfriendly"- with the exception of the Queen and Prince Philip.

And then there is this missile:"The fallout began at the time of the wedding in 2018. Really damaging things were said and done. The atmosphere soured hard and early,but few meaningful attempts were made by anyone to heal the wounds."

A poll released in Britain over the weekend suggests the public largely supports the wishes of the Duke and Duchess to go it alone,but most respondents were angry and disappointed by the couple's failure to tell the Queen before they made the announcement. There is huge affection for the 93-year-old monarch,and Prince Charles and Prince William also enjoy good public approval ratings.

But a damaging,no-holds-barred interview could change all that in an instant. It's why the most likely outcome of Monday's meeting at Sandringham is a win for Harry and Meghan and the cost of a permanent fracture at the heart of the royal family.