A recent tribunal decision has focused attention on whether Prince Charles's £700m estate is a separate entity that should pay corporation tax.
Last year, an information rights tribunal (Bruton v IC and the Duchy of Cornwall & the Attorney General to HRH the Prince of Wales (EA/2010/0182) ruled that the duchy was a separate public authority to the Prince of Wales under the Environmental Information Regulations.
Last week, the anti-monarchy group Republic wrote to both HMRC and the Commons Public Accounts Committee, asking them to look into the tax affairs of the Duchy of Cornwall. Republic argues that the duchy, which has been inherited by successive Prince of Wales' since the 14th century, is liable corporation tax and has been avoiding to do so.
The group's chief executive Graham Smith said: "Charles has avoided CT by claiming that there is no legal distinction between him and his duchy and that he already pays income tax. However, as reported in Saturday's Guardian, an information rights tribunal recently ruled that the duchy is a separate legal entity."
However, a spokesman for Prince Charles said he planned to appeal the environmental tribuanl ruling and Clarence House denied any avoidance claims.