Image caption Concerns have been raised in the past about Prince Charles's role in political matters.

David Cameron has no plans to change laws which require the government to seek Prince Charles's permission to pass legislation which could affect his private interests, Downing Street says.

It follows a Guardian report saying ministers have sought Charles's consent on at least 12 bills since 2005.

Subjects included gambling, coroners and the Olympics, the paper says.

Clarence House said this was a "long-standing convention" and was not about seeking the prince's personal views.

Neither Downing Street nor Clarence House would say whether bills were altered as a result of objections from the heir to the throne.

The newspaper, which obtained the documents following a Freedom of Information request to the House of Commons, said in the last two parliamentary sessions Charles had been asked to agree to bills on wreck removals and co-operative societies.

And, between 2007 and 2009, he was consulted on bills relating to coroners, economic development and construction, marine and coastal access, housing and regeneration, and energy and planning.

The prime minister's spokeswoman said it was "protocol" for the prince to be consulted over some legislation, citing the parliamentary guide book, Erskine May, which said his consent was required on bills that affected the principality of Wales, the earldom of Chester and the Duchy of Cornwall - his private business and property empire.

This is not about seeking the personal views of the prince but rather it is a long-standing convention in relation to the Duchy of Cornwall, which would have applied equally to his predecessors Clarence House

This power is different from the "royal assent" - a constitutional formality - the Queen gives all laws passed by Parliament.

The PM's spokeswoman added that she was aware of no plans to change this rule.

She would not say whether Downing Street was aware of any bills being changed as a result of this procedure.

A Clarence House spokesman said he would not comment on any correspondence between the government and the prince.

He did say however that parliamentary procedure meant Prince Charles, as the Duke of Cornwall, could be required to give his consent to bills directly affecting the interests of the Duchy.

"This is not about seeking the personal views of the prince but rather it is a long-standing convention in relation to the Duchy of Cornwall, which would have applied equally to his predecessors," he added.

Republic, which campaigns for an elected head of state, called on Clarence House and the government to publish details of all legislation altered as a result of what it called a "constitutional loophole allowing (Charles) to veto government bills".

Graham Smith, spokesman for Republic, said: "That such a loophole exists shows our constitution is fundamentally anti-democratic."

Concerns have been raised in the past about Prince Charles's role in political matters.

In 2009, the prince, who is known to have strong views on the environment, farming and architecture, was reported to have written to politicians in eight government departments, including the Treasury and Foreign and Commonwealth Office, since 2006.