Oprah Winfrey, the billionaire US talk show host and publisher, said on Monday she was “cleaning house” at her exclusive girls’ academy in South Africa after one of the teachers was charged with sexually abusing students.

In a video news conference beamed from Chicago to journalists in Johannesburg she said she had been “shaken to the core” and cried when she first heard of the allegations of abuse at her school. “This is one of the most devastating if not the most devastating experience of my life,” she said.