An explosive investigation by Channel 4’s Dispatches programme and The Sunday Times has opened a pandora’s box surrounding the Duchy of Cornwall.

The vast business empire includes a portfolio of land, properties and assets valued at more than £1-billion with the affairs of the private estate veiled in secrecy, until now.

The exposé lifts a lid for the first time on the finances of the Duchy which Prince William as the Duke of Cornwall, took over from his father in September 2022.

Both Dartmoor Prison at Princetown and Dartmoor National Park are part of that portfolio which brought in a distributable surplus of £23.6-million last year according to the Duchy’s annual accounts.

The Ministry of Defence and Ministry of Justice are paying for long-term leases on both areas - at a cost to the taxpayer.

Even the volume of air that the Tamar bridge occupies has a price tag, according to the Duchy. A licensing agreement from 2008 specifies the lease of a volume of air space for the road bridge over the water of Tamar, licensed up to 3007.

The two councils who jointly own the bridge are said to have paid £1000 in 2008 for the space the bridge takes up.

The Tamar Crossings authority also has annual fees to pay to the Duchy. A spokesperson for the crossings, said: “The Duchy owns the foreshore (coastline) and fundus (riverbed) around Cornwall and parts of south Devon, including the river Tamar.

“The Duchy therefore has rights to a proportion of the wayleaves income that we receive from telecommunications equipment, cables etc. installed in areas of the structure beyond the low water mark of the river below the Tamar Bridge. The income due to the Duchy last year was £7,071.50, 25% of the income received.

“At the Torpoint Ferry we pay an annual rent of £530 in relation to the utility of having our ferry chains lay on the river bed.  The ferry is a chain ferry operation in which the three vessels each uses a pair of chains across the river on which they pull themselves across the river.”

The Duchy of Cornwall earns money from the foreshore around Plymouth too which extends along the river Tamar to Saltash.

According to the investigation, a percentage of the harbour commissioner’s profits brings in £200,000 a year for the Duchy who charge for moorings, ferries and boat yards.

The foreshore of Cornwall is also charged out by the Duchy with the RNLI having to pay for five lifeboat stations to access the sea via slipways, with one further location in Devon.

A spokesperson for the RNLI said: “I can confirm that the RNLI pays a nominal rent in relation to six RNLI properties on land belonging to the Duchy of Cornwall.”

The five in Cornwall include Penlee, Rock, Sennen Cove, The Lizard and St Mary’s lifeboat stations. Together with Salcombe Lifeboat Station in Devon, the RNLI is charged £600 per year by the Duchy for all six sites.

A dossier compiled of all the Duchy’s land registry titles found that there is a 25-year leasehold deal with Dartmoor Prison in Devon, amounting in total to £37.5-million – the equivalent of £1.5-million a year – despite the prison being empty.

All 175 inmates were moved to other jails earlier this year after high levels of radon gas were detected in accommodation areas. All repairs to the prison are funded by the taxpayer.

The Ministry of Justice has a long-term lease on the prison site and is responsible for maintenance and improvements; a situation they say that is not unusual for long-term leases on public institutions.

The Duchy of Cornwall also owns a 67,500-acre share of Dartmoor National Park and charges feudal levies dating back to the 1800s, according to the investigation. It bills the British Army an undisclosed sum each year for the right to train on the land.

Despite operating as a commercial venture and providing income for both the King and Prince William, the Duchy is run as a private estate and therefore exempt from paying corporation and capital gains tax.

“Both estates claim they are not funded by the tax payer, but the prison example is one of many where they’re making a profit from the taxpayer” the documentary stated.

Questions were also asked about the sustainable stewardship vision which is said to be at the heart of everything the Duchy does.

Their Integrated Annual Report published in July this year stated: ‘We continue to view our role as protectors of a unique and precious heritage, which contains incredibly biodiverse ecosystems and natural resources, as well as the communities who live and work across the estate.’

This is at odds with the decision to allow a company to begin drilling in different locations around Cornwall including the old tin mining site at Wheal Vor, the programme said.

Local residents are concerned about the effect new mining will have on historic damage caused by mining in the past and have set up a group to campaign for its protection. They say 33 preliminary boreholes throughout the Wheal Vor area located within the Parish of Breage near Helston were granted in 2021, giving permission to drill.

Some 150 years ago, Wheal Vor mine was one of the biggest and most successful mines in the area.

The legacy of its mining history say residents, is that the water in that mine has become contaminated with metals. The whole ecosystem of local water ways are affected by pollution from the abandoned mines. They fear drilling and more mining will exaggerate the situation.

C4 Dispatches found 351 mineral rights titles owned by the Duchy of Cornwall and reports it has signed a deal to drill in 25 square miles of the Tamar Valley, an area of outstanding natural beauty.

A spokesperson for the Duchy said: “We have granted a number of three-year exploration licences and all licensees must ensure that their activities are in strict accordance with statutory requirements and meet high environmental standards.”

They say, they are engaging with the critical minerals industry in Cornwall to respond to the UK Government’s Industrial Strategy.

A Duchy of Cornwall spokesperson added: “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.”

The annual payment the Royal Family receives from the government is set to rise to £132-million in the next financial year, up from £7.9-million in 2011.

A spokesperson for the Duchy said: “The Prince of Wales is not entitled to the capital of the Duchy estate and therefore is not taxed on capital profits, which he does not receive. 

“However, The Prince of Wales voluntarily pays income tax at the appropriate level on the revenue surplus from the Duchy of Cornwall.”

British researcher, writer and campaigner Guy Shrubsole, concluded in the documentary: “Ultimately the Duchies should be dissolved and folded in to the Crown Estate where they have to give their profits to the exchequer, and then some of that comes back to us, the tax payer.

“This isn’t about whether you believe there should be a monarch or not, it’s simply about good management.”