Law to British People

This one has a historical background:

Brazil had slavery till May 13th 1888, when slavery was forbidden by the Aurea Law, signed by Princess Isabel. The slave trade was really huge. The British Kingdom wasn't happy with the Portuguese and Dutch slaves trading from Africa to the Brazilian Empire. So, the British Parlament approved the "Bill Aberdeen Law". This law allowed the Royal Navy to sink slave trade ships coming from Africa heading to Brazil.

So, how many ships were attacked by the Royal Navy ??? Nobody knows. There are no historic registers of how many ships were attacked.

When we say "it's a law to British People" we mean something exist but no one cares about. Do you have something like this in USA ???