Donors abandoned the charity Prince Harry founded in memory of his late mother when he left the UK, the chair of Sentebale has said amid a bitter media row in which she accused the prince of trying to “eject” her through “bullying” and “harassment”.

Sophie Chandauka told Sky News’s Sunday Morning with Trevor Phillips programme that there was a “significant correlation” between a drop in funders and the Duke of Sussex’s departure to the US after the controversy caused by his rift with the royal family.

It was “pretty obvious” the charity, which supports people with HIV and Aids in Lesotho and Botswana, had lost corporate sponsors and individual donors around that time but there was “no discussion” about it, she said, adding that trustees had told her it was “uncomfortable” with Prince Harry in the room.

Chandauka, a Zimbabwean lawyer, told the programme: “So when I arrived in July in 2023, of course the first thing you do is you open the annual report, you look at the board minutes to see what is going on in the organisation.

“I did a seven-year historical review of the financials, looking at our costs and looking at our revenue, so income, it was pretty obvious to me that we had lost quite a number of corporate sponsors.

“We’d lost some families, and we’d lost individuals who were donating to the organisation, and there was quite a significant correlation between the time the organisation started to see a departure of sort of major organisations, and Prince Harry’s departure from the UK itself.

“When you look at the board minutes, though, there is no discussion about what’s happening with respect to some of our most significant funders and then when you discuss with the senior executive team and ask why there isn’t a conversation about this – the answer is: ‘It’s really difficult to have this conversation because the instruction was, it’s an uncomfortable conversation to have with Prince Harry in the room.’”

She said: “Really, what Prince Harry wanted to do was to eject me from the organisation and this went on for months.

“It went on for months through bullying, harassment. I have documentation. There were board meetings where members of the executive team and external strategic advisers were sending me messages saying: ‘Should I interrupt? Should I stop this? Oh my gosh, this is so bad.’

“In fact, our strategic adviser for fundraising then sent me a message saying she wouldn’t want to ever attend any more board meetings or bring her colleagues because of the treatment.

The interview, trailed on Saturday and aired in full on Sunday morning, included allegations of “harassment and bullying at scale” from the prince towards the chair, after Harry and several others quit the organisation earlier this week.

Though Harry has not commented specifically on the bullying and harassment allegations, sources close to the prince said the claims were “completely baseless”.

A source close to the charity’s trustees and patrons who stood down last week said they “fully expected this publicity stunt” – meaning Chandauka’s comments – and reached their collective decision to quit with this in mind. They added they “remain firm in their resignation, for the good of the charity, and look forward to the adjudication of the truth”.

Two named former trustees have come out in support of the prince, with Kelello Lerotholi, who resigned from the charity this week, telling Sky News he did not recognise the allegations: “I can honestly say, in the meetings I was present in, there was never even a hint of such.”

Chandauka said the prince, who she said had not been to Africa for five years, had made moves against her, adding further trustees to the charity’s board in efforts to bolster his control. In a separate interview with the Financial Times, she said there was noticeable friction between the UK staff and those based in Lesotho, where most of the charity’s 500-plus workforce is based. She said the board felt “a loss of power and control and influence … ‘Oh my goodness, the Africans are taking over.’”

When Harry could not have her removed through a vote, because of a legal challenge, she alleges, he aimed to sabotage the charity, which he set up in 2006 in memory of his late mother, Diana, Princess of Wales.

Chandauka, who appeared on Sky News with another board member, the investment banker Iain Rawlinson, claimed the rift became public with the prince’s “unleashing of the Sussex machine” against her.

The Conservative peer Lynda Chalker, who served as a trustee for nearly two decades until November, described Chandauka as having an “almost dictatorial” style.