Shirley Ballas on Strictly and survival: ‘I always vowed that I would support women’

Thanks to ‘bullying men at the top’, Shirley Ballas was on the brink of quitting the dance world to become a fitness instructor. Then she was made ‘Strictly’ head judge. She tells Katie Rosseinsky about this year’s star cast, family grief, finding her voice and the unexpected emotional significance of rhinestones