Oprah Winfrey, the chat-show host, flew to South Africa at the weekend for crisis meetings over allegations of sexual misconduct at her exclusive girls’ school south of Johannesburg.

The visit, her second in fewer than ten days, followed an admission last week that serious claims of misconduct had been levelled against a matron at the Oprah Winfrey Leadership Academy for Girls, a multimillion-pound school for underprivileged children.

John Samuel, the chief executive of the academy, said in a brief statement that the South African police’s family violence, child protection and sexual offences unit (FCS) had been informed of the internal investigation.

“The inquiry is being conducted in a manner that supports the safe and nurturing environment of the academy, with minimal disruption to campus life. In addition, the academy is providing psychological support and counselling services to our learners,” he said in the statement, the only comment that the school has made on the affair. The alleged perpetrator had been removed from the campus and other measures were taken to ensure the safety and wellbeing of the pupils, he added.

The Afrikaner-language newspaper Rapport reported that the matron was alleged to have grabbed a girl by the throat and thrown her against the wall. Other alleged charges were that the “dorm parent” swore and screamed at the girls, assaulted them and sexually fondled at least one of them.

The alleged incidents came to light when one of the pupils ran away from the school because the reported abuse had become intolerable. Her parents informed the school.

Ms Winfrey, the undisputed queen of chat-show television, who was abused as a child, reportedly flew to the country just over a week ago, missing an important Hollywood engagement. She returned unexpectedly on Friday and left again on Sunday.

She met the school’s executive and private investigators and held a two-hour meeting with parents, who were flown to Johannesburg. A report by a private investigator who arrived from the US to conduct an inquiry with a South African investigator has been handed to the police.

Ms Winfrey issued a terse statement saying that she was taking the incident extremely seriously. “Nothing is more serious or devastating to me than an allegation of misconduct by an adult against any girl at the academy,” she said in her only comment on the incident.

The school at Henley on Klip, a tranquil town of mining cottages, has been beset by controversy since it took in 150 of the country’s poorest but brightest girls in January. Locals complained that they were excluded from cleaning and kitchen work at the school; the local police resented that private firms provided security. Neighbours said that the imposing building, surrounded by an electric fence, was an eyesore. Parents also said that overstringent security had interfered with family visits.

Ms Winfrey, who has no children and is known to the girls as “Mama Oprah”, described the opening of the school, in which she has invested £22 million from her charitable foundation, as “the proudest, greatest day of my life”. “I know when you educate a girl you educate a family, a community — you change the face of a nation,” she said. “This is everything I have ever worked for. Education is the best gift you can ever have as a kid.” Ms Winfrey, who helped to choose the first entrants from 5,000 applicants and has built a house in the school grounds, pledged to spend as much time as possible alongside her charges. To qualify, the girls had to show academic and leadership potential and have household incomes of less than £350 a month. The 28-building campus, built over 52 acres, resembles a luxury retreat more than a school. It contains classrooms, computers and science laboratories, a library and a theatre.

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