Retrospective Criminal Legislation - and Mens Rea?

Question

If mens rea is a condition in regard to criminal liability, and as Parliament has the authority to pass any retrospective legisltion. Could anybody explain how there can be any criminal liability(retrospectiveley) If what was previously done was legal.

Answer 1

Prohibitions that act retroactively are considered a philosophical blunder, though they've been known to happen before. It would be difficult in most western nations to hold somebody to account for something that wasn't a crime at the time, but not for the reasons you think.



Mens rea actually wouldn't be a problem, for the same reason that ignorance of the law is not an excuse. Mens rea does not necessarily involve the intent to violate the law; instead, it simply involves the intent to commit the act which violates the law. (There are exceptions where the crime itself actually requires knowledge of the wrongfulness of the act, but those are relatively few.)

Answer 2

Mens Rea would not typically be a problem because of the content of the mens rea. Usually mens rea is a state of mind with regard to the actus reus - e.g. GBHs 18 is causing grevious bodily harm with intent. The intent is the intent to cause GBH. It doesn't matter, from a mens rea point of view, whether causing GBH was illegal at the time it was done.



There might perhaps be some complexity to do with defences of Insanity, since it is necessary for a successful defence for the defendant to be unaware of the "nature or quality of his actions". "quality" is usually interpreted as being unaware of the difference between right and wrong, or (the other way round) the defendant is not insane if he knew what he was doing was illegal. Retrospective legislation might create some judicial head-scratching over insanity.



Although parliament *could* make retrospective legislation, so far as I know, since 1998 it hasn't. Probably the best example of retrospective legislation was not criminal, but civil - the Burma Oil case, in which parliament used its legislative power to overturn a court decision.

Answer 3

Parliament does not have power to pass retroactive criminal legislation. Human Rights legislation prevents you from being prosecuted for something that was not a crime when you did it.



This does not necessarily apply to civil law and the Courts have power to retroactively amend contracts.