In my experience, if the HT is a good one and is implementing the things that will work and is supporting their staff and encouraging them, then the ones who are not cut out for the job even after being helped will stand out. the HT should then be able to work through procedures to get rid of the teacher.
What I have seen is poor HTs who implement things that don't work in their school, who have teachers in their staff they don't like and would rather not have around,no matter how good they are. HTs who couldn't teach a satisfactory lesson never mind an outstanding one. Where support isn't given and so the teachers are ground down in the hope that they leave. Where HTs change the goal posts to get try and get rid of teachers who they perceive as rubbish when they could just use a bit of guidance and encouragement.
I have seen HT who shirk responsibilities during the school day and shut themselves off in their paperwork world, coming out to tell everyone they have got it wrong.
My DH had been producing outstanding and good lessons over a period of time, the HT changes and the new one says his lessons are unsatisfactory, disagreeing with Ofsted, LA link inspectors and consultants. Just because he taught in a way the HT did not like. DH changed his style to suit HT and what a surprise, back to good and outstanding. He raised the results and had the strongest dept in the school. Still working through forgiving this man who had turned our lives upside down by forcing DH to resign due to an admin error. Can't go into it but OH my goodness, you really have no idea. So much is down to the HT.
Re behaviour and class control, if there is a behaviour policy that is in place that the teacher tries to follow but when it gets to the point where Senior Management are involved and they don't do what they are supposed to by following up appropriately, then the children see that what should happen, doesn't and then the teachers are left not trusting the system or their bosses. Respect for Senior Management declines from children, staff and parents. Teachers are left having to deal with it in the classroom and maybe the dept as they know that going to the SMT is pointless. Under one HT, a child is excluded internally for swearing at a teacher, under another, if they apologise after causing no end of problem before even leaving the room, they expect the teacher to have them back in. What does this say to the other children. Isn't it funny that some HT have very sharp teeth for the staff but quite blunt when it comes to dealing with the outrageous behaviour from children and parents?
I am in despair to be honest. Yes crap teachers should be easy to get rid of as long as they have been supported properly to see of they are able to improve.
AAAAaaarrrrrrrrggggggggggggh. I am all cross again. There are so many unfair decisions made by the people who actually have the power. Who and what do they train HT because some one needs to look at the curriculum they use for HTs as it is lacking in my opinion. I am ranting and I don't care. Mr Gove, sort it out. Get you HTs sorted out and you'll see such a difference. I bloody hate this.