LONDON - Britain's Prince Charles said he will stop speaking out on issues he feels strongly about when he becomes king as he is "not that stupid".
Speaking to the BBC ahead of his 70th birthday next week, the son of 92-year-old Queen Elizabeth said that the role of monarch was completely different to his current position as Prince of Wales.
"The idea, somehow, that I'm going to go on in exactly the same way, if I have to succeed, is complete nonsense because the two - the two situations - are completely different," he said.
Asked whether his public campaigning will continue, he said: "No, it won't. I'm not that stupid."
Britain currently has a constitutional monarchy, where the monarch has a formal role in the formation of governments but an obligation to remain neutral and no practical political power.
Charles has been outspoken on topics such as the environment and social issues. In September Charles said in an interview with GQ magazine in September that "My problem is I find there are too many things that need doing or battling on behalf of."
But he told the BBC that he would operate within "constitutional parameters" as king.
"I do realise that it is a separate exercise being sovereign. So of course I understand entirely how that should operate," he said.
But he defended his activism as heir to the throne, which includes founding the Prince's Trust charity in 1976 to support vulnerable young people.
He said: "If it's meddling to worry about the inner cities as I did 40 years ago, then if that's meddling I'm proud of it."