"The Prince began his campaign years ago, he's been campaigning for over half a century on the environment," Richard told the British publication.
The commentator went on to say that while people initially didn’t take Charles seriously, he has kept up his sustainable ventures, so there is a chance we may still here of it in his Christmas broadcast.
He added: "But remember it isn't a party political issue, it is something that almost all governments in the world now support. That is the reduction of carbon emissions."
"So the Prince wouldn't be straying into controversial territory by mentioning it," Richard said.
The royal expert concluded by saying that as King of England, Charles may prefer to deal with directly with the PM for environmental matters and not be a “campaigning monarch”.
The royal revelation comes after Charles recently admitted there is more work to be done when it comes to preventing future natural disasters and pandemics.
Speaking during an interview on Sky News, the 71-year-old said he considers himself lucky to have overcome the illness, but confessed more work needs to be done to prevent outbreaks.
“It makes me even more determined to push and shout and prod,” Charles told royal correspondent Rhiannon Mills.
“I was lucky in my case and got away with it quite lightly. But I've had it, and I can so understand what other people have gone through,” he said.