Buckingham Palace is facing accusations that it has buried an inquiry into bullying allegations made about the Duchess of Sussex.
In the year since the inquiry was launched, just four or five members of the Sussexes' 25-person team have been spoken to, the Daily Mail has reported.
Those who have been asked to provide evidence have reportedly not heard anything since last summer.
No findings from the probe have been published by the Palace and it is unclear when they will be brought to light.
One source told the Daily Mail : "This should have been an opportunity to do the right thing. Now it looks like they're going to do nothing instead.
"It has been a very difficult situation for all involved, but the Palace is a very powerful institution and there clearly seems to be a cultural problem of not handling bullying, particularly when you consider some of the allegations about the way Prince Andrew is said to have treated his staff over the years."
An internal inquiry into bullying claims was launched by palace aides last March.
It has been claimed that Meghan Markle's behaviour led to two personal assistants quitting their jobs and a third losing confidence in themselves.
The Duke and Duchess' former communications chief Jason Knauf reportedly submitted an email alleging unacceptable behaviour by the Duchess in 2018.
It is claimed to have been the spark that prompted Prince William to separate his household from the Sussexes.
Historian Robert Lacey claims an angry phone call between the brothers ended in Harry hanging up as they clashed over claims the Duchess of Sussex left at least one worker suffering post traumatic stress disorder (PTSD) due to the "toxic" environment.
William "went ballistic" when he heard the allegations, and later instructed his private secretary, Simon Case, to begin dividing their households "immediately", it is claimed.
The claims have been branded a "calculated smear campaign" by the Sussexes, who fiercely deny any wrongdoing.
In a statement issued in March last year, Harry and Meghan said: "We are disappointed to see this defamatory portrayal of The Duchess of Sussex given credibility by a media outlet.
"It’s no coincidence that distorted several-year-old accusations aimed at undermining The Duchess are being briefed to the British media shortly before she and The Duke are due to speak openly and honestly about their experience of recent years.
"In a detailed legal letter of rebuttal to The Times, we have addressed these defamatory claims in full, including spurious allegations regarding the use of gifts loaned to The Duchess by The Crown.
"The Duchess is saddened by this latest attack on her character, particularly as someone who has been the target of bullying herself and is deeply committed to supporting those who have experienced pain and trauma.
"She is determined to continue her work building compassion around the world and will keep striving to set an example for doing what is right and doing what is good."
The Palace refused to comment on the status of the investigation this week.
At the time the bullying claims came to air, a spokesperson for the Palace said: "We are clearly very concerned about allegations in The Times following claims made by former staff of the Duke and Duchess of Sussex.
"Accordingly our HR team will look into the circumstances outlined in the article. Members of staff involved at the time, including those who have left the household, will be invited to participate to see if lessons can be learned.
"The Royal Household has had a Dignity at Work policy in place for a number of years and does not and will not tolerate bullying or harassment in the workplace."
