Which document prohibited courts from detaining defendants without formal charges?

The document that is responsible for prohibiting courts from detaining defendants without formal charges is the Habeas Corpus Act. This legal principle, particularly represented in the Habeas Corpus Act of 1679, emphasizes the right of individuals to not be held in custody without sufficient cause or formal charges. It enables a person to challenge the legality of their detention and ensures that a court must review the reasons for their imprisonment.

While the Magna Carta also laid the groundwork for due process and legal rights, its focus was more broadly on limiting the powers of the crown and ensuring certain legal protections to subjects, rather than explicitly addressing the detention of defendants without charges. The Statute of Westminster and the Petition of Right, while important documents in the history of English law, do not directly concern the issue of unlawful detention in the same way the Habeas Corpus Act does. Hence, the correct response pertains specifically to the principles established by the Habeas Corpus Act.