LONDON (AFP) - Britain's royal family has slammed the BBC over a documentary that claimed a behind-the-scenes briefing war erupted before Prince Harry and his wife Meghan quit frontline duties.

"The Princes and the Press" dwelt on how Harry and his elder brother William have handled the media as they rose to adult prominence following the tragic death of their mother Diana in 1997.

The first of two episodes, which aired on Monday night (Nov 22), suggested that Harry in particular had a hostile attitude to the media, which worsened after he started dating US actress Meghan Markle in 2016.

The programme claimed palace insiders drip-fed the media with negative stories about the initially popular Harry and Meghan, as a power battle played out behind palace walls.

But it also reported that Harry sabotaged positive press coverage of a Middle East tour by his father Prince Charles, when he issued a blistering statement defending Meghan against unfavourable headlines.

"A free, responsible and open press is of vital importance to a healthy democracy," said a rare joint statement by the three royal households representing Queen Elizabeth II, Charles and William, which was included in the programme. "However, too often it is overblown and unfounded claims from unnamed sources that are presented as facts and it is disappointing when anyone, including the BBC, gives them credibility."

The royal family could boycott the national broadcaster in future, reports said. "Nothing is ruled out," The Sun newspaper reported, citing a senior royal source.

War of the Waleses

William and Harry were already furious at the BBC after a judicial inquiry confirmed that journalist Martin Bashir used false pretences to obtain a bombshell interview with their mother in 1995.

In the interview, Diana admitted adultery and famously said "there were three people" in her marriage - herself, Charles and his future wife Camilla Parker-Bowles.

Diana died aged 36 in a high-speed car crash while being chased by paparazzi photographers in Paris. Charles married Camilla in a low-key civil ceremony in 2005.

"The Princes and the Press" said that while Harry had never shed his loathing of the press since Diana's death, William had come to an accommodation, granting limited access in return for favourable coverage.

"He's in a much better place (with the press) than his brother," the source told The Sun, insisting that William had banned his staff from briefing against other royals. "He'd lived through that in the '90s with his parents in the 'War of the Waleses' and doesn't ever want it happening again."

The new BBC programme also discussed Meghan's alleged bullying of royal staff, which Buckingham Palace is investigating internally.

A lawyer for the former "Suits" star appeared on air to deny the claims. Citing media intrusion, Harry and Meghan quit royal life last year and now live in the United States, where they have signed a series of lucrative media deals and spoken out on a range of causes.

They have also openly criticised Britain's most famous family, including accusing an unnamed senior member of racism.

This month, Meghan apologised to a UK court after admitting to having cooperated with the authors of a fawning biography, having previously denied it.

The royal family meanwhile is braced for more legal fallout affecting Charles' younger brother, Prince Andrew, over his links to late US financier Jeffrey Epstein.