Alan, who got to know the heir by directing television and radio shows with him, said he was originally a fan of the drama.
But he added, “I don’t watch this show because I’m afraid I’m one of those who think it’s too much based on guesswork, and will move on to received wisdom.
“I know Prince Charles pretty well. And I would feel the same as any friend of mine pictured on the box.
“I feel loyal to them.”
Alan, who returns with his ITV show Love Your Weekend next year, said many people think the Netflix show is quite accurate and despises Netflix’s denials.
He said, “They say, ‘Oh, well, this is a drama. But no, that’s the life of real people.
“If I had to make a movie about your life, and make up songs that I didn’t know, that wouldn’t be very fair to you, would it?” I think it’s not enough to say, “Oh, people know this is a drama”.
“A lot of people don’t, a lot of people assume it’s true. ”
Alan admitted that he did enjoy some aspects of the show, however.
He said of the actress who played the queen: “I thought Claire Foy was wonderful. It was well cliché, it was delicious. It was instructive.
“I think when you get too far away from the present and start imagining what’s going on in a room with people… high level, then you start to affect how others perceive them with your imagination. … good thing.
“These are real people who have had complex lives… that you don’t know exist. You play with people’s lives.
The fourth series covers Charles’ marriage to Diana, his eating disorder, and his affair with Camilla Parker Bowles.
Other friends of Prince Charles have accused Netflix producers of “trolling a Hollywood budget.”
Among the contested scenes is Charles who verbally abuses his wife and Diana confronts him about his affair during their wedding rehearsal.
Earl Mountbatten is shown telling Charles that the family is disappointed with his relationship with Camilla.
* Love Your Weekend with Alan Titchmarsh returns Sunday January 3 at 10 a.m. on ITV.