Princess Diana's conversations were being recorded by the intelligence services, a former bodyguard has told the inquest into her death.
Ken Wharfe was Diana's bodyguard for six years
Ken Wharfe, who served Diana for six years, said the "Squidgygate" tapes of Diana speaking intimately to a friend in 1989 were probably made by GCHQ.
Transcripts in which the friend, James Gilbey, called Diana "Squidgy" were published in a national newspaper.
Diana and Dodi Al Fayed died in Paris after a car crash in August 1997.
Mr Wharfe told the central London hearing he believed the surveillance service GCHQ had broadcast the recording of the phone conversation over the airwaves for radio enthusiasts to pick up.
"It's my belief this internal recording was probably made by GCHQ... they probably had a good reason for doing it," he said.
"For some unknown reason this conversation is released on a loop to allow (radio enthusiasts)... to pick them up."
He added that he believed GCHQ were monitoring members of the royal family due to heightened IRA activity at the time.
The recorded conversation took place on New Year's Eve 1989 while Diana was staying at the Queen's Sandringham Estate in Norfolk. Mr Gilbey was on a mobile phone.
Mr Wharfe said Diana was concerned about the tape "purely from an embarrassment point of view".
However, he said the Queen told the princess she was unhappy about what had happened and ordered an inquiry.
He also told the inquest jury how the Queen did not support her work with organisations dealing with HIV/Aids.
He said that on one occasion, Diana told him: "The Queen doesn't like me getting involved with Aids... [and said] 'Why don't you get involved with something more pleasant?'"
The princess was the first in the royal family to have contact with a patient affected by the illness, at a time when many people still did not know how the infection was passed on.
"I think Diana was very angry and annoyed the Queen could not see what she was doing," he said.
He also said the princess's aides had made the mistake of "alienating" the media rather than working with them.
Richard Horwell, representing the Metropolitan Police at the hearing, said Diana had requested that Mr Wharfe was removed from her police protection team.
Mr Horwell said she had lost confidence in him and suspected he had been talking to the press about her.
In response, Mr Wharfe told the jury he was "astounded" to hear that and claimed Diana's behaviour had become a "bit odd" and she was becoming suspicious of her security team.
The inquest continues.