From the Magna Carta, the basis of Western law since 1215:

'38 In future no official shall place a man on trial upon his own unsupported statement, without producing credible witnesses to the truth of it.

'39 No free man shall be seized or imprisoned, or stripped of his rights or possessions, or outlawed or exiled, or deprived of his standing in any other way, nor will we proceed with force against him, or send others to do so, except by the lawful judgment of his equals or by the law of the land.'

First They Came For The Terrorists...