A royal journalist claims staff working for Prince Harry and Meghan Markle faced "loyalty tests" while working within Kensington Palace.
Valentine Low, who writes for UK paper The Times, says staff would often say, "I feel sick" or "I'm shaking" before encountering the royal couple.
He claimed Prince Harry had been unhappy with both the media and his own staff for a while before meeting Meghan, but the situation only got worse after the two got married.
In his book, Courtiers: The Hidden Power Behind The Crown, a source told Low that Harry "definitely had mistrust of the courtiers at Buckingham Palace and his father's palace."
"He would use this phrase the whole time, 'the palace syndrome', when you won't fight the battles he wants, because you have been institutionalised.
"Giving in to the media was a key symptom of whether you had developed it. It was a constant test of loyalty: 'Are you going to protect me? Or have you just become one of them, who won't fight for me?' It was exhausting," the source said.
Low also said on a UK TV breakfast show there had been a group of staff who branded themselves the "Sussex Survivors' Club" after a number of troubling encounters with Harry and Meghan.
"I think it was a very difficult experience for some of them," Low said.
"As I revealed last year, there were allegations that Meghan bullied staff. People talked to me of people being completely destroyed.
"I've heard people at the time, faced with a possible encounter with Meghan, were saying things like 'I feel sick' or 'I'm shaking' – extraordinary things for an employee to say about the prospect of seeing their employer in half-an-hour."
In March last year, the Duchess had to vehemently deny bombshell accusations she mistreated staff and left them "humiliated" and "shaking with fear".
According to The Times, a complaint was filed by the couple's then communications secretary, alleging that several royal aides had been bullied by the Duchess of Sussex.
Jason Knauf - a New Zealander who previously worked as a communications adviser for Prime Minister Helen Clark - reportedly claimed Meghan "drove two personal assistants out of the household and was undermining the confidence of a third staff member" in an email to Simon Case, the then-private secretary to Prince William.
A number of "serious concerns" about "unacceptable treatment" were allegedly raised in the complaint, said to be sent in October 2018. The Times reported Knauf was attempting to "protect staff who he claimed were coming under pressure from the Duchess".
A spokesperson for Meghan dismissed the accusations at the time as "a calculated smear campaign based on misleading and harmful misinformation".
In the wake of the claims, Buckingham Palace hired a private law firm to investigate accusations against Markle after The Times of London published an article saying a complaint was filed by the couple's then communications secretary, in October 2018, alleging that several royal aides had been bullied by the Duchess of Sussex.
As a result, Markle was cleared of the accusations, but Buckingham Palace said it wouldn't release the results of the report.