Teaching unions in Birmingham have hit out at government plans which will see schools facing tougher exam and pupil performance targets.
In a manifesto pledge in the run-up to the General Election, Prime Minister David Cameron promised the Tories would declare a war on "mediocrity" in schools.
He said "coasting schools", deemed by Ofsted to be "requiring improvement", could be turned into academies and their headteachers sacked - potentially affecting 60 schools in Birmingham.
Now, the Conservative Government is swiftly forging ahead with its plans, introducing the new Education and Adoption Bill and further defining what it means by "coasting schools".
The bill would see the introduction of new, tougher targets which would see some schools rated as 'good' by Ofsted facing the "coasting" label.
The new threshold for secondary schools will require 60 per cent of pupils to achieve five good GCSEs, including English and maths - 20 per cent higher than the existing 40 per cent threshold.
Every primary school will be required to have 85 per cent or more of its pupils achieving the benchmark standard in reading, maths and writing in their SATs tests - another 20 per cent hike on the existing 65 per cent target.
"I'm unapologetic about shining a spotlight on complacency," said Education Secretary Nicky Morgan.
"For too long, a group of coasting schools, many in leafy areas with more advantages than schools in disadvantaged communities, have fallen beneath the radar."
The Department for Education said "hundreds" of schools would have to raise their results.
But Birmingham-based teaching union NASUWT said it would lead to more schools becoming academies - a move it opposes.
General Secretary Chris Keates said: "It should come as no surprise to anyone the secretary of state is selecting criteria to define coasting schools to maximise the opportunity for extending academisation.
"It signals more uncertainty and turbulence for schools, distracting them from focusing on raising standards. Every child should benefit from an education which enables them to reach their potential.
"However, ministers are wilfully ignoring the damaging conditions they have created in which children no longer have the right to be taught by qualified teachers."