Recently been observed by a HMI that was invited in by the school. As a result the quality of teaching was 'inadequate' which I don't dispute. What I am concerned about is what the school have put in place as a result under the guise of a 'support' plan. They've given me a mentor and opportunities to observe other teachers across the school, which is good for helping me develop professionally. But they've also informed me that they are going to do 'drop-ins' of 20 minutes and make a judgement against the quality of learning, with no prior notice. I know the school have done this to other teachers previously after they had been observed twice as 'inadequate'. I have also been observed 4 previous times this year, as satisfactory, good, satisfactory and outstanding, for my previous observation. I'd like to know if this is happening anywhere else and should I be getting my union involved? The school is an academy btw.