But government says a host of Oxbridge offers at academy schools shows the system is working.
National Education Union is now calling for the government to step in, after Ofsted "failed to act" on a number of troubling allegations.
Shadow education secretary unveils schools overhaul at conference.
'We have to think radically about how we bring about a more just and more equal society'
Driverless cars, the 'Northern Powerhouse' and more
'Kids need to relax, have fun, have cuddles on the sofa, watch a movie, play.'