The law goes into effect at the end of August, leading many teachers to go ahead and defriend their students, even as one journalism high school teacher questions whether it violates his First Amendment speech rights.

FORBES: Why Missouri's Ban on Teacher-Student Facebook Friendships Is Doomed

Head teacher Gwyn Tudur said he "questions a system which allows such a big change".

BBC: Wales school banding is a failure, teaching unions claim

As a professional school teacher, I am saddened that the public in most African countries does not ask hard questions.

BBC: You are in: Talking Point

But education and parent teacher groups criticised the survey by North Yorkshire County Council, which contained more than 100 questions - half of which were about drugs and drug abuse and 26 others about sex.

BBC: Schoolchildren quizzed on drug habits