Any school that doesn't get 'good' or 'outstanding' is going to be failing. Which presumably makes them ripe for academy-ing.
That means my DC secondary school - that was outstanding in 2010 - was rated as satisfactory this year. And DH's special school - slated for not putting enough children up for GCSEs (some of whom are pre-verbal and most of whom have passed a major milestone when they sit in a chair for a whole lesson).