Obviously something has gone seriously wrong here, and it may well be that the school/governing body/LEA/Health Authority are accountable to some degree if the teacher was declared fit to teach when he wasn't. None of us know the details.
And it's equally obvious that of course no pupil should ever be assaulted by a teacher.
However, I do agree with those who say that maybe this sad case will highlight the ludicrous position thousands of teachers are put in on a daily basis. I am a teacher. Over the course of my career I have known many colleagues who have been abused, verbally, physically, had their property stolen, damaged, had threats made against them etc. I think part of the solution here has to be for schools to make far more use of the criminal justice system against pupils who abuse and assault teachers.
I have known only two teachers who have 'fought back'. One was a younger colleague from many years ago who taught a 15 year old girl who threatened to 'cut up' the teacher's young child. This teacher got the police to press charges against the girl, even though the school were keen to get her to 'reslove the situation amicably' because the girl concerned wasn't very bright and came from a difficult background! Yeah right, so that makes it ok to make threats to kill does it?
The second case was someone I know who as a deputy head, punished a lad for bringing alcohol into school. The pupil subsequently made a malicious allegation of a sexual nature against the deputy head. The allegation was dismissed out of hand by the police who investigated, but the stress on the deputy was enormous. For most teachers who are victims of malicious allegations, the fact that they don't end up being charged is usually enough - they leave the matter at that and are relieved to leave it behind. Thank goodness, this deputy had the strength of mind to NOT leave it at that. He successfully took action against the boy for making a malicious allegation. The boy concerned was very bright, and looking forward to University and a successful career - let's hope having a criminal record will now put paid to that.
Schools need to exercise a proper duty of care to their staff - and IMO this means being far more prepared to involve the police. You wouldn't get away with swearing out, spitting at, pushing or hitting a passer by in the street. Why should anyone get away with it just because they are in a classroom?