Re: Police would definitely use that information against them if they got the chance
"And yet it is their duty to arrest anyone whom they see (or hear about) breaking the law. How on earth can they do that if they don't know the law themselves?"
Again - as already stated - they have a WORKING knowledge of the law. They're trained to do the job, not be lawyers.
Again: It's the job of the CPS to figure out precisely what laws were broken after the bill have pried the proverbial two parties off of each other and mopped up the blood.
And you can still sick them for illegal arrest or harassment if they balls it up.
It takes years to qualify to be a solicitor, and then you earn a ton of money. Do you honestly believe it's viable for our policemen to be trained to those standards of familiarity with the law?
What do you want: Policemen who are au fait on a working level with the law, or to triple the salray of every policeman.
Because those are your choices.
"Yet our legal system insists that every citizen must act as if he knew every law in detail."
No, it doesn't. That's not how our legal system works. It expects us to act as a reasonable person would. Ignorance is no excuse when it comes to the morally obvious, but it's a perfectly acceptable defence when it comes to intricacies that a reasonable member of the public would not understand, have exposure to, or be likely to take legal advice over.