Other findings include that the royals charge a fee for the right to cross rivers and run cables under the beaches they own.

They also earn passive income from tolls, parking lots and wind turbines, the investigation found.

The doc also included a series of examples showing that William’s estate clashed with the values laid out in his Earthshot Prize.

The campaign, founded by the future king in 2020, focuses on highlighting efficient ways of preserving the planet.

The findings also revealed the duchy’s $48 million deal to lease Dartmoor Prison, located in England, to the Ministry of Justice.

Both estates have raised around $65 million through deals made in the past year, the doc adds.

In response to the investigation, a Duchy of Cornwall spokesperson told The Post, “The Duchy of Cornwall is a private estate with a commercial imperative which we achieve alongside our commitment to restoring the natural environment and generating positive social impact for our communities.

“Prince William became Duke of Cornwall in September 2022 and since then has committed to an expansive transformation of the Duchy.”

“This includes a significant investment to make the estate net zero by the end of 2032, as well as establishing targeted mental health support for our tenants and working with local partners to help tackle homelessness in Cornwall,” they added.

The Post has reached out to Buckingham Palace for comment.

Earlier this year, William’s eye-popping $30 million salary was revealed. He received the income from his Duchy of Cornwall estate during the 2023-2024 financial year.

The Integrated Annual Report revealed a $30.4 million surplus for the 2023-2024 financial year, as well as William’s new Duke of Cornwall title.

However, the father of three raised eyebrows by refusing to reveal what he paid in taxes for the 2023-2024 financial year — breaking his father’s tradition that spanned more than 30 years.