@Peter 2
"And you can't legitimately complain about not enforcing a law on offenses prior to the date the law was passed either, as retroactivity (the act of doing something, and then having a law made against it and being punished for something that wasn't illegal when you did it) is banned under both the universal & EU human rights laws."
I completely concur on your thought processes, but there have been several cases of laws in the UK that act retrospectively. Tax changes for instance have been made retrospective. Don't know how they expect you to avoid breaking a law that isn't even in existence at the time, but it's now happening.