Make collective punishment illegal in u.k schools.

In the interests of fairness, to punish all the children of a class because of misbehaviour of one or two cannot be acceptable.
It demoralises the children who try hard to be good and are consistently well behaved members of the class. Many well behaved children find this collective punishment very upsetting and unfair.
It also encourages bullying - in the sense that by using peer pressure as a form of control to bully the mis-behaving child into behaving because the rest of the class are expected to be upset at being punished for another child's poor behaviour.
This is outdated and there are many better methods of improving behaviour from children.