The head of a charity co-founded by the Duke of Sussex has called his brand "toxic" and claimed it hindered the group, after he and several others quit the organisation earlier this week.

Speaking to the Financial Times, Sentebale chairwoman Dr Sophie Chandauka said she first felt tensions with Prince Harry a year ago.

Dr Chandauka separately told Sky News the way the duke handled his departure from the charity, set up in 2006 in honour of his mother, Diana, to help people in southern Africa living with HIV and Aids, amounted to "harassment and bullying at scale".

A source close to the former trustees and patrons said they "fully expected this publicity stunt".

"They remain firm in their resignation, for the good of the charity, and look forward to the adjudication of the truth," the source added.

BBC News has approached Sentebale for comment.

Prince Harry has said he and co-founder Prince Seeiso of Lesotho stepped down because the relationship between the charity's trustees and Dr Chandauka "broke down beyond repair".

But Dr Chandauka strongly defended her record as chair, adding: "The number-one risk for this organisation was the toxicity of its lead patron's brand."

Dr Chandauka, who was on Sentebale's board before becoming chair, accused Prince Harry of wanting "to force a failure and then come to the rescue".

But she told them: "The team is resolved that Sentebele will live on, with or without you."

Elsewhere, she argued that various controversies around Prince Harry following his relocation to the US had affected the charity's ability to diversify its donor pool and hire people.

"When you start to interview people, they're asking questions about, well, these mixed messages around the patron," she said.

She said she first felt tension between Prince Harry and herself a year ago.

She also claimed the duke's team asked her to defend his wife, Meghan, from negative publicity.

"I said no, we're not setting a precedent by which we become an extension of the Sussex PR machine," she said.

In a separate interview with Sky News, Dr Chandauka was sharply critical of the way in which Prince Harry resigned.

She said the only reason she was speaking up is because the duke this week "authorised the release of a damaging piece of news to the outside world without informing me or my country directors, or my executive director".

"And can you imagine what that attack has done for me, on me and the 540 individuals in the Sentebale organisations and their family?" she said.

"That is an example of harassment and bullying at scale."

Prince Harry founded Sentebale in 2006. The charity has been hugely important to him and a massive part of his adult life.

So his decision to walk away from it, along with his co-founder Prince Seeiso, is hugely significant.

In a joint statement on Wednesday, the duke and Prince Seeiso said they were resigning from their roles with "heavy hearts" and in "solidarity with the board of trustees".

"It is devastating that the relationship between the charity's trustees and the chair of the board broke down beyond repair, creating an untenable situation," they said.

They said the trustees "acted in the best interest of the charity" by asking Dr Chandauka to step down, but her decision to take legal action to retain her position was "further underscoring the broken relationship".

They added they would be sharing their concerns with the Charity Commission "as to how this came about".

Dr Chandauka said she had "blown the whistle" about issues including what she described as abuse of power, bullying, sexism and racism.

She said her work at Sentebale had been "guided by the principles of fairness and equitable treatment for all", and that she had reported the trustees to the UK Charity Commission.

The charity itself has confirmed a "restructuring" of its board.

Former trustees Timothy Boucher, Mark Dyer, Audrey Kgosidintsi, Dr Kelello Lerotholi and Damian West described their decision as "nothing short of devastating" for all of them.

They said they had lost trust and confidence in the chairwoman but her legal action to block them from removing her meant they had no other option than to resign.

The Charity Commission has said it was "aware of concerns" over Sentebale's governance, adding: "We are assessing the issues to determine the appropriate regulatory steps."