Prince Charles's Duchy of Cornwall estate condemned over non-disclosure of 'private' property deals - including £38.4m Waitrose warehouse

The Treasury has refused to provide details of property deals worth more than £100m which it has approved on behalf of Prince Charles and his Duchy of Cornwall estate by insisting that the transactions are “private” and exempt from disclosure rules.

George Osborne’s department has rejected a Freedom of Information request from The Independent seeking disclosure of dozens of deals by the Duchy’s managers following the revelation that the estate spent £38.4m to add a supermarket warehouse to its substantial property portfolio.

Campaigners condemned the decision to withhold the records saying it placed the scrutiny of the Duchy behind a curtain of secrecy and means the public cannot be certain that the Treasury is holding the vast estate - run to provide an income for the heir to the throne - to account.

The Duchy has bought and sold dozens of properties and land parcels over the last five years in deals scrutinised by the Treasury as part of its statutory duty to ensure the estate, worth £763m, is “well-managed” and maximises the income it pays to Charles and his future heirs.

The Duchy is facing growing calls to increase the transparency of its dealings despite the insistence of royal officials that it is a “private” body which is not funded by the tax payer. It also facing separate questions from MPs about why it is exempt from corporation and capital gains taxes.

The Treasury has a statutory obligation to approve every property transaction by the estate worth £500,000 or more. Under arcane arrangements dating back to the 19th Century, the deals are scrutinised by Government whips acting under the title of Lord Commissioners of the Treasury.

But the department only reveals the total value of each transaction and whether it involves a sale or a purchase, meaning that the precise location or nature of a property remains secret and the make-up of the commercial empire held on behalf of the prince for the good of the nation remains unknown.

The Independent, which earlier this year revealed the purchase of the sprawling Waitrose distribution hub in Milton Keynes in apparent contradiction to Charles’s well-known dislike of architectural “carbuncles”, asked the Treasury to explain which other property deals it had approved.

In a four-page letter rejecting the request, the Treasury described the Duchy as a “private estate” despite a recent judicial ruling that it constitutes a “public body” and insisted the need to protect the Duchy’s commercial confidence - and so prevent it from being out-bid on properties or presented with inflated price demands - outweighed the public interest.

It said: “The review recognised there is a general public interest in transparency to inform debate. However, there is also a strong case for non-disclosure, as release would be likely to harm the commercial interests of the Duchy of Cornwall and the commercial interests of the other parties to these transactions.”

Campaigners rejected the argument put forward by Clarence House that the Duchy is a private entity and accused governments past and present of wrongly preserving the “secrecy” surrounding the estate’s dealings.

Graham Smith, of anti-monarchy group Republic, said: “Despite what Clarence House would like us to think, the Duchy isn’t Charles’s personal property - it belongs to the nation. How can we be certain that the Treasury is holding the Duchy to account on our behalf if we can’t see the evidence?”

A Duchy of Cornwall Spokesperson said: The Duchy of Cornwall is a private estate, not a public body. Therefore, like any other private organization, the Duchy is entitled to commercial confidentiality."