British law vs say Roman law.
Because of the widespread nature of the British empire remnants of these laws (and remnants of the Empire, such as the Queen being formally the supreme being in Canada) are still found all over the world, even if a lot of those laws have been abolished in the UK itself.
I think you mean English common law. There's not such thing as "British law" as such, because Scotland has its own legal system (which incidently is partly based on Roman law).
So maybe they're not that crazy :)