I'm going to try to find out from my daughter about the Tadcaster school - she became a teaching assistant there last Summer and I also know, and used to work with, one of the teachers. It all sounds very odd.
Violence in schools? Mid 1980's a girl (high on glue) swayed in front of me, threatening me with open scissors. It has become more frequent, especially since we were stopped from searching pupils' bags (I think that right may have been re-established, a serving teacher may up-date me).
Then, in the early 2000's, there was the kid (from a family known to be associated with drugs) who threatened me with a gun (turned out to be an imitation, but I didn't know that) when I was shepherding a lot of smaller children across the playground.
A lot of children have started carrying knives for self-protection and that has accelerated the level of violence, but it is hard to blame them. Teacher searches might help a lot.