My youngest has just gone through secondary school and is now at college.
Her secondary school used to employ a lot of teachers straight from university because they are cheap. Their future careers are based upon results (and that of the school come to that). Consequently they don't 'teach' any more, they concentrate on passing exams. In her last year, most of her effort was spent on previous exam papers. Whilst her grades were okay, I wonder what she actually learnt because although bright, I don't think she is doing as well as she should be at college because she is missing some of foundations that are needed for the next level of exams.
She is not alone though and I'm sure that it stems from the previous school using so many teachers without any real world experience. Of course they all need to start somewhere, but it seems the teachers are thrown straight in at the deep end and are given little time to develop the skills they should need.
There is a big turn-over of teachers and I'm sure that a lot of them leave the profession because they rarely get the opportunity to actually teach.