The Prince of Wales says he will stop speaking out on topics he feels strongly about when he becomes king, as he is “not that stupid”.
He has campaigned on issues such as the environment for decades, but says he would not do the same as monarch.
Speaking in a BBC documentary to mark his 70th birthday, Prince Charles said the idea that he would continue making interventions was “nonsense”.
He said he would have to operate within “constitutional parameters”.
He has campaigned on issues including the environment, wildlife preservation, architecture and the use of GM crops.
In the hour-long programme, he was asked about what some people have called his “meddling”, but said he had always tried to remain “non-party political”.
He said: “I think it’s vital to remember there’s only room for one sovereign at a time, not two.
“So, you can’t be the same as the sovereign if you’re the Prince of Wales or the heir.
“But 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.”
Asked whether his public campaigning would continue, he said: “No, it won’t. I’m not that stupid.
“I do realise that it is a separate exercise being sovereign. So of course I understand entirely how that should operate.”
Documentary film maker John Bridcut, who followed the royal for 12 months, said Prince Charles “bridled a bit” at the use of the word meddling, and instead preferred to think of his interventions as “motivating”.
The heir to the throne 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.”