Presumption of innocence
The presumption of innocence is a principle that places the burden of proof on the prosecution to prove beyond a reasonable doubt that a criminal defendant is guilty, not on the defendant to prove his innocence. The principle is considered to be a fundamental part of due process. The presumption of innocence has its origin in the English common law and is fundamental to legal systems, such as those of the United States, which are derived from common law. The presumption of innocence has also become part of many systems of civil law, and is now seen throughout the world as an essential element of human freedom.
The presumption of innocence was summarized by Viscount Sankey thus, in the context of a murder trial: "If, at the end of and on the whole of the case, there is a reasonable doubt, created by the evidence given by either the prosecution or the prisoner, as to whether the prisoner killed the deceased with a malicious intention, the prosecution has not made out the case and the prisoner is entitled to an acquittal."  In the same speech, he referred to this legal principle as the "golden thread" running "throughout the web of the English Criminal Law", a phrase which has come to be used as a shorthand for the principle itself.