LONDON — A British television channel on Monday defended its decision to broadcast recordings of Princess Diana candidly discussing her personal life, after some royal watchers called it a betrayal of the late princess’ privacy.

Channel 4 said the video tapes, made in the early 1990s, are an “important historical source” and place Diana “front and center” in her own story as Britain marks 20 years since her death.

The channel said that although the recordings were made in private, “the subjects covered are a matter of public record and provide a unique insight into the preparations Diana undertook to gain a public voice and tell her own personal story.”

Diana Spencer and Prince Charles married in 1981 and had two sons, Prince William and Prince Harry. They separated in 1992, eventually divorcing in 1996. Diana died in a car crash in Paris in August 1997. She was 36.

The recordings of Diana talking to voice coach Peter Settelen were made at the princess’ Kensington Palace residence, and include discussion of her failing marriage and Charles’ relationship with his then-mistress Camilla Parker Bowles.

Rosa Monckton, a friend of Diana, said broadcasting the tapes was “a betrayal of her privacy and of the family’s privacy.”

Former royal spokesman Dickie Arbiter told Sky News it was “absolutely shameful” that the tapes were being broadcast.

Police held the videotapes after they were seized in ex-royal butler Paul Burrell’s home in 2001. Diana’s family tried to make a legal claim to the recordings, but they were returned to Settelen in 2004.

Portions of the recordings were broadcast by U.S. network NBC in 2004, but they have never been shown in Britain.

They feature in a Channel 4 documentary that is due to air Sunday.

William and Harry’s Kensington Palace office declined to comment on the documentary.