Sadly, a great number of secondary school teachers (especially inner city ones) risk a chinning - but thats naturally hushed up by the school.
In my career, I can recount many incidences where severe threats were made on staff, but thankfully were rarely followed up - but there were a few.
Dramatically there were 6 student deaths (by violence) in my time.
Naturally it was the same hard cases (or their families) on every occasion.
When I started teaching (1974) violence was often fuelled by alcohol - usually by parents or 'big brothers' after school.
When I left (2007) the incidences of severe violence were less - due to dope replacing booze.
I personally was never targetted (nice guy etc) but was shot at (once), had an arson attack (once) and was ram raided (once). The only time someone stuck the boot in was when I was splitting up a girls fight.
That won't be mentioned in any Ofsted report!
......and its still the best job in the world, and the vast majority of kids are a real credit to their parents.
John