Anti-royalists will descend on Cornwall today to rally support for a campaign to abolish the Duchy of Cornwall, Prince Charles' £728m land and property portfolio.
Campaigners want the 53,000-hectare estate, most of which lies in the south-west, to be handed over to local people to boost the rural economy.
The protest comes amid growing disquiet in the region that the Duchy may be putting its own financial interests before those of the community.
The Duchy of Cornwall, which provides an income for the Prince, his sons and the Duchess of Cambridge, owns land in 23 counties and made a profit of £18m last year.
In June, it pushed through a plan to build one hundred houses and a Waitrose store on quality farmland east of Truro. Local councillor, Bert Biscoe, said the development marked the beginning of "the battle for Cornwall's land." He said: "Charles does not accept his constitutional responsibilities to Cornwall, he just wants the money. He says 'stand up for rural life and the farmer', and then builds a supermarket and a hundred houses on good quality farmland."
The £40m Truro East District Centre received planning permission earlier this year. More than 250 letters of objection were written by local residents who feared that the development would become "another Poundbury" – a reference to the "experimental" town near Dorchester, built to Prince Charles' own architectural specifications.
The Duchy's origins lie deep in England's medieval past. Created in 1337 by Edward III to provide an income for his son, the Black Prince, it has propped up heirs to the throne ever since. The charter that created the Duchy remains a controversial document for Cornish nationalists, who interpret it as a piece of political manoeuvring to keep unruly Cornish landowners within the English fold.
Republic, whose ultimate goal is the abolition of the monarchy, are launching the campaign at a public meeting in Truro. "This land is the property of the Crown, which means it belongs to the nation," said Graham Smith, Republic's campaign manager. "The Duchy has to be got rid of as an institution. It could be gifted to the people of Cornwall." Mr Smith is expecting a warm reception in Truro, where a republican "summit" will be held in the local library this afternoon.
Mr Smith said the campaign was not about "the independence or status of Cornwall", but part of "a wider campaign to curtail Charles' interference and influence in politics."
In recent years the Duchy has angered residents of the Isles of Scilly by driving up the rents on the islands, Mr Smith said. The Duchy states on its website that it is working with housing associations on the islands to provide 18 new affordable homes.
A spokesman for the Duchy of Cornwall declined to comment on Republic's campaign for the estate's demise. When asked about the fairness of the Duchy's funding model, the spokesman said their accounts were "transparent and black and white".
According to the Duchy's website, the Duke "chooses to use a large proportion of the income from the Duchy to meet the cost of his public and charitable work. The Duchy also funds the public, charitable and private activities of the Duchess of Cornwall and Princes William and Harry."
"The Duchy has been run like this since 1337 and I don't think we'll be saying anymore than that," a spokesman said.