Media playback is unsupported on your device Media caption Nicky Morgan: "Where schools don't have a plan to help students progress we will intervene"

Coasting schools will face quicker government intervention, Education Secretary Nicky Morgan has said.

Under new plans, ministers could force schools rated as "requiring improvement" and missing new government benchmarks to become an academy.

Coasting schools have average results which have often flatlined over time.

Mrs Morgan told the BBC that results show that "students do do better in academies".

"Where it is clear that a school does not have the capacity or the plan to get themselves out of 'requires improvement'... then yes we will intervene, we will put in support... and of course we will look at the academy model too," she told BBC One's The Andrew Marr Show.

Mrs Morgan said academies are "fantastic schools" because they "give power to heads and teachers", but she would not give a target for the number of schools that could adopt that model.

She also ruled out profit making organisations running schools.

"I think the best people to run schools are the heads, the teachers and the governors," she said.

But Kevin Courtney, deputy secretary of the National Union of Teachers (NUT) told the BBC there was "no convincing evidence" that academies improve standards.

"This is serious error that the government is making. They are following something which has no evidence base," he said.

The proposals will be in a new bill due to be introduced in the Queen's Speech.

'Expert head teachers'

Mrs Morgan said the education bill would focus on schools that are in special measures and those that are known as coasting schools.

Writing in the Sunday Telegraph, Mrs Morgan said coasting schools will be put on an immediate notice to improve and could then be taken over and turned into an academy.

They will be required to work with a team of "expert" head teachers.

Mr Courtney said it was unclear what a "coasting" school actually was.

"For some people it seems to be suggesting that every school has to be above average, and that is statistically impossible," he told the BBC.

He said the NUT wants schools to improve but wants to look at evidence on how to improve schools.

More than 3,300 schools in England are labelled "requires improvement", but the plans are unlikely to cover that many schools.

Under the current system, secondary schools are considered to be failing, and therefore eligible for intervention, if fewer than 40% of their students score at least five Cs at GCSE, including English and maths, and they do not meet national averages in pupil progress.

In primary schools, the threshold for intervention is if fewer than 65% of pupils get Level 4 in reading, writing and maths and a below average number of pupils make the expected amount of progress.

It is not yet clear how coasting schools will be deemed in need of intervention.

It is understood that a new category will be devised covering schools which are rated as "requires improvement" and which fail to meet a new set of standards on improvement.