Margaret McGuckin, who went into care at the age of three, said that the abuse she suffered started almost immediately.
She said: "I'd be beaten, trailed around and be near drowned in baths or with disinfectant. To be slapped and beaten with hard canes... and be locked in dark cupboards and rooms for hours."
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A total of 8,648 sailors died during the largest naval engagement during the First World War, which marks its centenary on Tuesday.
The figures by the Global Slavery Index are a third higher than previously thought.
Sara Di Pietrantonio, 22, died in Rome on Sunday.