Kate Middleton and Camilla Parker Bowles
The BBC has postponed its documentary Reinventing the Royals after lawyers representing the Royal Family are believed to have intervened.Getty

Clarence House has reportedly intervened to stop the BBC from broadcasting a damning documentary which shows the Royal Family attempting to win back public support after the death of Princess Diana.

Reinventing the Royals, which was due to air on Sunday, claims that the Prince of Wales hired a new press secretary to boost his image and integrate Camilla Parker Bowles into palace life – a campaign dubbed "Operation Mrs PB".

The schedule was reportedly changed after a letter from Prince Charles and the Duchess of Cornwall.

According to the Radio Times, the documentary, which was presented by former Panorama editor Steve Hewlett, was pulled from the 9pm slot after lawyers "known to represent senior members of the royal family" had made contact.

But a statement from the BBC reads: "The BBC is delaying broadcast of the documentary Reinventing The Royals, due to be shown on BBC Two on January 4, until later in the New Year while a number of issues including the use of archive footage are resolved."

The footage includes the first-ever television interview with Sandy Henney, who was press secretary to Prince Charles when Diana died.

Henney reveals that Charles was becoming increasingly concerned that his image was "in tatters" even before the accident that killed the Princess of Wales.

"(Charles) was getting some pretty virulent criticism - bad father, unloving husband," Ms Henney said in the documentary.

"I think he was pretty hurt... if you've got a middle-aged balding man and a beautiful princess, it's a no-brainer as to who is going to get the media coverage."

The decision to postpone the broadcast until later in the New Year is believed to have been taken by James Harding, head of BBC news and current affairs.

The Royal Family has not commented on the broadcast.