An anti-monarchy group is launching a campaign to "abolish" the Duchy of Cornwall in what it says is an attempt to make the royal family more accountable.
Members of the Republic group will meet residents in Cornwall - one of the heartlands of both support for and opposition to the Duchy - during a "summit" next Saturday.
Their aim is to "get rid" of the private estate, which funds the public, charitable and private activities of Charles and his family.
Much of the Duchy's land is in the South West of England, where the Prince and his family are regular visitors.
Republic chief executive Graham Smith said: "The monarchy needs to be held to account (and) open to scrutiny - abolition of the Duchy will be a step in that direction.
"We will be launching the campaign in Cornwall. We want to hear what Cornish people have to say about the future of the Duchy. But this is a national issue and we'll be campaigning on it up and down the country."
The Prince is admired across much of Cornwall, partly through his close links with the county, and his support is boosted by regular public appearances.
He is patron of the Royal Cornwall Agricultural Association, which runs the county's annual show and of which he was joint president with Camilla, the Duchess of Cornwall, in 2010.
But the Duchy's involvement with Waitrose and Cornwall Council in a retail and accommodation development on the edge of Truro city centre has upset some residents and business leaders, who are concerned about the impact the "urban sprawl" will have on existing traders and traffic.
Republic, which campaigns for a "democratic Britain with an elected head of state", will this year begin campaigning to include the royals in Freedom of Information laws and to abolish the royal veto over legislation.