A charity founded by the author JK Rowling has announced that its chief executive is to step down and it is to commission two independent reviews of governance and culture.
The Harry Potter author set up Lumos in 2005 to support children growing up in families rather than institutions. She remains life president.
Neil Blair, Rowling's agent and chair of Lumos, said in a statement that the board had recently identified "some management and culture challenges facing Lumos that require immediate action".
He said it was the right time for new leadership and therefore Georgette Mulheir, who has led the foundation since 2011, would be stepping down.
"The charity will be led by the executive leadership team with an interim managing director while the search for the new chief executive is under way," said Blair.
Mulheir, he added, would begin a new global strategic advisory role for the charity "in the coming months".
The statement did not include any quotes from Mulheir or say how she felt about the arrangement.
Blair said the two reviews were necessary to "ensure that Lumos continues to be an organisation that holds itself to the highest standards".
He added: "We will take all necessary steps in response to the findings."
Asked why Mulheir was not being given the chance to address the challenges, a spokeswoman said: "Due to rapid growth, the needs of Lumos today are different from when Georgette Mulheir took on the chief executive role in 2011. As a result, the nature and complexity of the chief executive role have also scaled."
Lumos has received sharp criticism from current and former employees on the recruitment website Glassdoor, which allows staff to rate their places of work.
One, who worked there for three years, said there was a huge discrepancy between pay for average employees and senior management, and that bullying took place.
Another wrote: "The senior management need to take a hard long look at themselves, the mess they have created and how they treat long-serving and hard-working staff."
But others were more supportive. "The recent restructure has been hard on staff; however, the majority can see the rationale and that improvements are being made," wrote one.
According to the charity's latest accounts, for the financial year ending 31 December 2017, it earned £8.8m and its highest-paid member of staff received a total package of between £160,000 and £170,000.
Total remuneration for key management personnel more than doubled, from £355,498 to £755,112. The spokeswoman said this covered 11 people globally.
She said the charity, which employs 91 staff, did not comment on individual salaries but all core costs were funded by Lumos's 100 per cent pledge, under which Rowling and others have agreed to cover the charity's administration and overhead costs.
The charity has received £18m from the rights of Rowling's 2007 book The Tales of Beedle the Bard.
Asked why pay to key management personnel had risen so much, she said: "Lumos has been through a period of rapid growth and operational requirements have changed as a result.
"We’ve grown from a Europe-focused charity to one working globally across multiple countries and bolstered our leadership accordingly."
The spokeswoman added that Rowling was "aware of these changes and supports the actions taken".