The “Habeas Corpus Act” was passed in the reign of Charles II., and defined a provision of similar character in Magna Charta, to which also it added certain details. The Act provides
(1) That any man taken to prison can insist that the person who charges him with crime shall bring him bodily before a judge, and state the why and wherefore of his detention. As soon as this is done, the judge is to decide whether or not the accused is to be admitted to bail. [No one, therefore, can be imprisoned on mere suspicion, and no one can be left in prison any indefinite time at the caprice of the powers that be. Imprisonment, in fact, must be either for punishment after conviction, or for safe custody till the time of trial.]
(2) It provides that every person accused of crime shall have the question of his guilt decided by a jury of twelve men, and not by a Government agent or nominee.
(3) No prisoner can be tried a second time on the same charge.
(4) Every prisoner may insist on being examined within twenty days of his arrest, and tried by jury the next session.
(5) No defendant is to be sent to prison beyond the seas, either within or without the British dominions.
The exact meaning of the words Habeas Corpus is this: “You are to produce the body.” That is, You, the accuser, are to bring before the judge the body of the accused, that he may be tried and receive the award of the court, and you (the accused) are to abide by the award of the judge.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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