Financial assets known as bona vacantia, owned by people who died without a will or known next of kin, are collected by the duchy. Over the last 10 years, it has collected more than £60m in the funds. It has long claimed that, after deducting costs, bona vacantia revenues are donated to charities.

However, only a small percentage of these revenues is being given to charity. Internal duchy documents seen by the Guardian reveal how funds are secretly being used to finance the renovation of properties that are owned by the king and rented out for profit.