But, the new addition to their home has sparked outrage as the bill is expected to be footed by the tax-payer.
The panic room is reported to be part of an estimated $8.8 million security bill that will be covered by the Sovereign Grant, a source told The Mirror.
However, former royal protection officer Ken Wharfe revealed that the property will need to undergo drastic work to keep it secure.
“There is no protection at Frogmore, there is no one living there,” he said.
“There will have to be major reviews of the security surrounding that property, exposed on virtually every side.”
In fact, the luxurious property is only 200 metres from a public path and standing between the cottage is a small fence which could easily be scaled.
But the updates are set to cost a pretty penny.
“It’s a mammoth task. The costs of fitting and maintaining security equipment, with further officers in the area, could cost further millions each year,” Ken added.
“It’ll be a dramatic rise to the taxpayer.”