I have read books on Diana, Princess of Wales and I can say Prince Charles did make embarrassing comments in public to Diana.
Yeah, I can agree with that. There was the infamous comment where he said he wished he had two wives so he could send both of them on opposite sides of the royal walkabout so he could re-direct traffic.
Honestly though, I think Diana did more public sniping but after reading Wharfe's book, I think its irrelevant. Their private relationship was vile and what got reported in public didn't always match what was going on in private. Some incidences where it was claimed she was showing Charles up, Wharfe maintained that she really just wanted to get away from the Royal Family and the press. Other incidences that didn't get much press coverage, Wharfe claimed that she was trying to show Charles up and was disappointed in the lack of coverage. Conversely, the first public function Charles and Diana did together after their separation where everyone was amazed at how well they got on and wondered whether they were going to get back together, Wharfe maintains it was just an act. He quoted Charles as responding to a question, 'How do you two do it?' and Charles said 'Smoke and mirrors'
The funniest incident (at least to me, not to Wharfe, he was irritated) was the trip that Diana and her boys took to Disney World. Disney had a VIP pass that allowed guests to use private walkways and underground tunnels to the rides and cut in line so they would have the most privacy. This was a big complaint against Diana in that she claimed to want normalcy but took advantage of perks to let her cut in line. Wharfe maintains that she did NOT want the VIP pass; she said she didn't want to be seen as taking advantage. He overruled her because of security issues.
He suspected that something was up with her because she was in a vile mood; so he had a guest check and found that Richard Kay was booked into one of the hotels. Kay was the only name he recognized and was known for having direct contact with Diana. So Wharfe suspected Diana of actually wanting to court publicity to show up Charles which was the real reason for her not wanting the VIP pass. However, she maintained to him that she did not want publicity. Wharfe was peeved at her not being honest with him which he maintained was vital for his role as her security guard so he decided to take her at her word and stave off any attempts by the press to get a scoop.
He reported that despite the best security measures, some of the press always showed up at the very rides they were going on and Disney World is big. He suspected that Diana was consistently clueing somebody in to let them know where she'd be. But every time the press tried to get their shot, either he or Disney thwarted them so they didn't get their scoop.
As the trip wore on, he reported that Diana got more and more pissed and difficult to deal with but he took a tactic from Charles' book and let her stew. Initially in the book, he was very critical of Charles' ignoring Diana and I had to agree with him. I think Charles took the easy way out and just left the servants to deal with her which was unfair to her and to the servants. But by the end of the book, Wharfe was handling her like Charles was.
Maybe this is Schadenfreude but I did enjoy reading how Diana got so pissed at her own security guard for thwarting her attempts to do something underhanded. In this incident, I thought she deserved exactly what she got.
As an American, I also enjoyed the fact that despite Wharfe's rather superior condescending towards Americans regarding security (he claimed credit for thwarting the press at Disney) there were quite a few incidents where he didn't even need to get involved, Disney's security measures were quite capable of handing the onslaught of the Diana press mob.