The law is made up by people though, and people often get things wrong.
For example I had to do my speed awareness course because I got caught doing 60 on a dual carriageway. Yes the national speed limit is 70 on a dual carriageway, yes half a mile along the same road the speed limit was 70, yes 2 years previously the speed limit where I was caught was 70, but it had been reduced to 50.
OK I was caught breaking the rules, but if it's 'right' for that bit of road to have a 50mph speed limit then the previous limit was wrong, ie the law was wrong.