Ignorantia Juris non excusat

Ignorantia juris non excusat or Ignorantia legis neminem excusat (Latin for "ignorance of the law does not excuse" or "ignorance of the law excuses no one") is a public policy holding that a person who is unaware of a law may not escape liability for violating that law merely because he or she was unaware of its content; that is, persons have presumed knowledge of the law.
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Ignorance of the law is no excuse
If committing an offence a guilty party cannot use as a defence the fact that they did so without knowledge that they were breaking the law