Forty-five students, among them young children, were discovered held in chains in a basement when police raided an Islamic seminary in Pakistan last night.

The male students, some said to be as young as 12 but appearing even younger, were found in what amounted to a dungeon at the Madrassa Zakarya in the Sohrab Goth district of Karachi.

Led barefoot from their prison, captives told officers they had suffered regular beatings and been hung upside down as a form of punishment.