Details of the royal family’s finances, including rent received from the NHS, schools and the armed forces, have been revealed as part of a new documentary.

In the investigation conducted by Dispatches and the Sunday TimesThe private estates of King Charles and Prince William are believed to have received millions of pounds in income from contracts with public bodies and charities.

Over the past year, these deals with the Duchies of Lancaster and Cornwall are estimated to have cost almost £50 million, it has been claimed.

A spokesperson for the Duchy of Lancaster, King Charles’ private estate, said it “complies with all UK laws and regulatory standards applicable to its range of business activities”.

The Duchy of Lancaster, established in 1399, and Prince William’s Duchy of Cornwall, established in 1337, both hold large amounts of land and commercial property in England and Wales.

Their contracts with public bodies reportedly include a £37 million deal between the Duchy of Cornwall and the Ministry of Justice to lease Dartmoor Prison, as well as an £11.4 million deal between Guy’s and St Thomas’ NHS Trust and the Duchy of Lancaster for hire. a London warehouse over 15 years.

The Dispatches’ The King, The Prince and Their Secret Millions reports that details of the rental agreements have not been communicated to Parliament.

The documentary raises concerns about the environmental impact of some of the estates’ contracts, particularly those with mining companies.

The two private estates are distinct from the Crown Estate, a collection of land and properties which operate as a private business and belong to the “sovereign for the duration of his reign”.

The royal family receives the sovereign grant, expressed as a percentage of the profits from the Crown Estate, intended to cover operating costs. It will hit £132m next yearafter Crown Estate profits rose to £1.1 billion.

A spokesperson for the Duchy of Cornwall said it was “a private estate with a commercial imperative which we deliver alongside our commitment to restoring the natural environment and generating positive social impact for our communities” .

On the mining issue, the spokesperson said the duchy was “acting responsibly and sustainably” in relation to the government’s industrial strategy.

A spokesperson for the Duchy of Lancaster said it operated “as a trading company, managing a wide range of land and property assets across England and Wales”.

They said that the duchy “delegates certain functions, notably those relating to asset management, to the Duchy Council” and that while the king “takes a close interest” in the work of the duchy, the day-to-day management of the portfolio is the responsibility . of the board and the executive team.

He added that he had made “a number of key environmental improvements in recent years”.