By Alexis Akwagyiram
Prince Charles circulated journals among close friends and contacts
Prince Charles is taking legal action against the Mail on Sunday after it printed extracts from diaries he kept during a 1997 visit to Hong Kong.
BBC News considers the constitutional issues thrown up by the case.
The Prince of Wales' High Court attempt to stop further publication of extracts from his journals has prompted questions about what he can and cannot say, and how this may change if he becomes king.
During the case, Mark Bolland, the prince's private secretary between 1996 and 2002, said Charles saw himself as a "dissident" working against political opinion.
The documents include a 3,000-word journal referred to as The Handover of Hong Kong - or The Great Chinese Takeaway.
In extracts about the 1997 Hong Kong handover published in the Mail on Sunday in November 2005, the prince described Chinese officials as "appalling old waxworks".
In another reported extract from the documents, he described one ceremony as an "awful Soviet-style" performance and dismissed a speech by the then Chinese president as propaganda.
But is the heir to the throne entitled to adopt such strong views?
BBC Royal Correspondent Peter Hunt believes there is no immediate problem with the role that the prince has "created himself".
But he said the "key danger" that the prince's officials feared was that Charles could be perceived as a "dissident king" if he were to become the monarch.
"It lies at the heart of Mark Bolland's witness statement. He [Mr Bolland] said he and other senior advisers tried to dampen down the prince's behaviour in making public his thoughts and views on a whole range of issues.
"The reason, he says, was that an essential part of preparing the prince to be king in future was that he didn't make so many controversial comments because it conflicts with the monarch's constitutional role. I think that is at the heart of the concern here."
'King in waiting'
He said the prince's aides would stress that Charles would alter his behaviour if he became king.
"The privilege of his current position, which he has carved out for himself, is that he can speak out and he is fully aware that he will have to shut up when he becomes king," said Mr Hunt.
William Shawcross, the Queen Mother's official biographer, believes the prince is justified in wanting to comment on certain issues.
"I think the prince has a very difficult position. He is a king in waiting," he said.
"He is a man with a strong conscience and strong views and he expresses these views.
"He sees his job as to express views that are not always politically popular. He doesn't take politically partisan stands on issues."
The prince has been outspoken on issues such as climate change
But not everyone agrees.
Tristram Hunt, an author and historian, agreed that by discussing issues such as GM crops and the environment, the prince was not dealing with traditional party politics, but he said "politics has changed".
Mr Hunt said such comments were "doing damage to the monarchy" because some of the prince's views now "fall within a party political framework" and had been "clumsy" interventions.
The historian cited the foot-and-mouth outbreak and the Human Rights Act as issues on which prince had become involved in a public debate.
He said Charles' habit in the past of putting out memos and briefing newspapers had "backfired" overall, even though the prince had "tapped into popular concerns" on issues such as climate change and GM crops.
Expressing his belief that the prince's observations were often ill-advised, Mr Hunt said: "It is a rather dangerous road to go down - it can come back to bite you.
"If you are thinking about the longevity of the British monarchy you have to take a more considered view than the next splash on News 24."
And his sentiments were echoed by Phil Hall, a former editor of the News of the World.
He suggested that the prince's behaviour already verged on being unconstitutional and were ill-advised because, being the heir to the throne, Charles' views on certain issues will be widely known if he becomes king.
"I think he sees himself as above the law because the constitutional rules are very, very clear. A head of state is not to put his political views on the public stage, and this is what he is doing," said Mr Hall.
"We are a 100% democracy. This is a man who has been born into this privilege and he has this access. And I think he is using it against the rules.
"We had a Prince of Wales not so long ago who thought the Nazis were a good idea. That is an extreme view, I know, but Prince Charles should not be using his position to influence political debate."