Prince Charles is guilty of a clear conflict of interest in lobbying on issues from which he has made a large profit.
That's the view of Republic, which has condemned Prince Charles's failure to declare his investments that have now been revealed by the Guardian.
Charles invested in Sustainable Forestry Management, an offshore company run by one of his friends, before embarking on a campaign to promote forest protection policies.
Graham Smith, speaking for Republic, said today:
"Charles has secretly invested in a company that may well have benefitted enormously from his lobbying and public speeches. At no time did Charles declare his personal financial interest in this issue."
"We must be able to expect the highest standards from a future head of state. Yet Charles, who is already receiving millions from the taxpayer and public estates, is investing in his friend's offshore company and using his position to ramp up the share value."
"Charles has always made a virtue of his close involvement in the management of the Duchy. He cannot now blame officials or accountants."
"Any other public official or politician would be sacked for this kind of behaviour. It is a clear abuse of public office."
"MPs need to demand transparency over royal financial interests. Whatever rules apply to them, should apply to the royals."
"Like the Queen, Charles is also actively seeking to avoid paying tax - it appears the royals can't do enough to keep hold of their money."
Prince Charles has often made it clear he actively runs the Duchy. The Duchy of Cornwall's website states:
"The current Duke is actively involved in running the Duchy and his philosophy is to improve the estate and pass it on to future Dukes in a stronger and better condition. The Prince of Wales takes a long-term stewardship approach and has proved that environmental and agricultural best practice are compatible with a sound financial return. The Duchy capital account has increased from £408m to £763m since 2004, and the surplus has increased £9.9m to £19m over the same period.
The "board" of the Duchy is The Prince's Council, which meets twice a year and is chaired by His Royal Highness. With the exception of the Secretary and Keeper of the Records, The Prince's Council is a non-executive body which provides advice to His Royal Highness with regard to the management of the Duchy."