Answer: Originally the Government had proposed this. However the text that still stands in the legislation states.
“Where it is clear that the local authority can no longer viably support its remaining schools because too many schools have already become academies.”
The issue here is that it is not an arbitrary 50% but rather an assessment based on viability, currently roughly 30-35% of Birmingham Schools are academies so there is still a large number managed directly by the LEA and a long way to go before the viability test potentially will be failed.
It is partly for this reason that it is important that schools do not “Jump before they are pushed” as the more that jump the greater the chance the rest will be pushed.