I would like to take this opportunity to make an important announcement, it concerns socks.
The sock law concerns PE in British secondary schools, and it effectively states this "Pupils should not where the same socks in PE as they do while in lessons."
My first thought here is "WHY!" A sock will not kill you, there is no magical force field which disintegrates you if it detects certain socks in a PE area, there are no snipers that will shoot children stone dead. there is not point!
It is truly health and safety, gone mad. Although this may disappoint you, it is not actually a law but an encouraged guideline (a little bit of legal protection going on there).