The Royal Family has received millions of pounds of income in rent from the NHS, schools and the armed forces, a new documentary has revealed.

In the investigation by Channel 4’s Dispatches and the Sunday Times, it is reported that the private estates of King Charles and Prince William hold contracts with public bodies and charities.

Dame Margaret Hodge told the BBC on Sunday the findings have raised “serious question marks” and has called for a “full and transparent review” of both duchies.

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

Over the past year, deals made by the Duchies of Lancaster and Cornwall have raised around £50 million, it has been claimed.

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 are said to include a £37.5 million agreement between the Duchy of Cornwall and the Ministry of Justice to lease Dartmoor Prison, and a £11.4 million deal between Guy’s and St Thomas’ NHS Trust and the Duchy of Lancaster to rent a London warehouse over 15 years to store ambulances.

The estates also reportedly charge the Ministry of Defence for access to moor boats and refuel warships, some state schools to use their properties, and a local borough council to operate a toll bridge.

The estates are not subject to corporation tax and the royals do not pay capital gains tax on the assets they sell. They voluntarily pay income tax on the surplus.

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

The report points out that the duchies say they are not funded by taxpayers, but they do receive income from public services.

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

The two private estates are separate to the Crown Estate.

Profits from the Crown Estate – a property business owned by the monarch but run independently – go to the Treasury. The level of profit made by the Crown Estate is used as a benchmark to calculate the funding given by the government to the Royal Family in the form of the Sovereign Grant.

The taxpayer-funded Sovereign Grant will rise to £132 million in the next financial year, after profits from the Crown Estate increased to £1.1 billion.

Dame Hodge, a former chair of the Public Accounts Committee said: “We all love the monarchy, we all want it to work. But we want them to lead by example in the way they conduct their finances.

“They don’t pay capital gains tax and they don’t pay corporation tax, yet they claim to act commercially,” she said.

“But they can’t have it both ways. If they want to be private and commercial they have to pay the fair rate of tax as everyone else does, otherwise they get a competitive advantage”.

A Duchy of Cornwall spokesperson said it 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”.

On the issue of mining, the spokesperson said that the duchy was “acting responsibly and in a sustainable way” in line with the government’s industrial strategy, which encourages investment in domestic sources of minerals.

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

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

It added it had made “a number of key environmental improvements in recent years”.