PRINCE CHARLES is livid over reports that he’s having a secret love affair with his secretary behind the back of longtime mistress Camilla Parker-Bowles.

And Camilla is fuming.

“She’s so upset by the news that she doesn’t want to hear Charles’ denials,” an insider revealed.

“Camilla has long suspected an affair between Charles and his secretary Elizabeth Buchanan. Camilla even got Elizabeth’s name struck off the permanent guest list for official functions at St. James’ Palace!”

The controversy began after Elizabeth, 39, discovered her car had been broken into while parked at a horse ranch near her family home in mid-May.

Elizabeth was upset because some 60 love letters from Prince Charles were missing from her car after the break-in, the German magazine Gala disclosed.

Gala also revealed that “a personal computer, regularly used by Charles, and important security passes for the royal palaces were also stolen. Charles had little choice but to report the theft to Scotland Yard.”

The Gala article added: “During the last few months the Royal Protection Officers managed to ‘miss’ not less than 73 private trips that charles made to see his private secretary in her luxurious London apartment. She lives in Kensington, not far from the palace.”

Diana was furious in 1993 when Charles hired beautiful “Tiggy” Legge-bourke to be his assistant private secretary.

But the RPO’s job is to accompany Charles wherever he goes and keep a record of his travels. “Even when Charles wants to spend sme private time the Royal Protection Officers will know about it and keep a detailed record of every trip,” said Gala.

The Paris magazine France Dimanche also reported the stolen love letters and asked readers: “Why did Charles have the need to write to a colleague that he saw every day? And why did Elizabeth carry the letters from her employer in her bag? It is not necessary to be a great detective in order to divine the reason: The young woman is evidently in love with her illustrious employer!”

Gala’s London correspondent Kurt Striegler told The ENQUIRER:

“We have very reliable sources in St. James’ Palace who are quite familiar with who is coming and going there. The sources are Prince Charles’ own staff. Elizabeth was often seen coming and going from the palace and Charles made 73 trips to her private apartment.

“This is nothing new. He cheated on Princess Diana and now he’s cheating on Camilla.

“Of course Charles is outraged that the love affair is public. It iscreating ahug stir in the palace and causing him severe embarrassment.”

The insider told The ENQUIRER: “Charles hit the roof when he read the stories about his affair with Elizabeth because he knew Camilla would be furious. He knew Camilla suspected something was going on.

“Charles told a friend: ‘Camilla is convinced the story is true and she’s in a rage about it. All I can do is deny it but I am sure Camilla doesn’t believe any of it.’

“Camilla is just waiting to see if the stolen letters turn up in the press. When and if they do, she’ll have it out with Charles!”