I do sympathise, though my experience isn't half as bad as yours. nor even in the same league. I too have had many students over the years, but my first one in a new school (with a new university) was a nightmare. Like you say; ignored all advice, told me what I should do, spoke badly about me in the staffroom (not that she got any sympathy), told her tutor I was a nightmare to work with, and so on. My HT was a fabulous support and listened to my tearful concerns, frustrations and hurts several times. If you didn't this time, I would definitely recommend keeping them fully informed. (I'm primary, might be a different person in secondary.) To be honest, in future I would have involved the university tutor from an earlier stage (the student was struggling a little as a teacher anyway) and to a greater degree. By the time I did, I think it was too little too late. It is hurtful when someone throws it all back in your face. But your boss and the university know the real situation and so will not think the worse of you. This student has lost any chance of a reference or a post in your school or in any where your boss knows the HT appointing. In the long run they will be the one suffering. My student has no hope of a teaching post in her current school (she is a TA), nor in mine, nor in any where either HT knows the prospective HT. Best of luck with the next student. You will get over this in the end. Until you do there is always G&Ts!