To be honest, this would never work in the UK. The simple reason being that the class would sit there bitching that the teacher spoiled it for them. Then after that they'd go crying to to their mommies and their mommies would go crying to the Daily Mail about what an awful teacher their little babies must face. The teacher would wind up losing their job for being described by the Daily Mail as an abusive wannabe pedophile whose greatest aspiration in life would be to become Jimmy Saville.

Sadly, this is what the UK has become.