“We will turn every failing and coasting secondary school into an academy.”

So said the 2015 Conservative election manifesto, which resulted in David Cameron returning to 10 Downing Street with an unexpected majority - and Nicky Morgan reappointed education secretary.

Now, it seems like a different era. A year after the first set of schools were officially deemed to be coasting, none of the almost-500 maintained primaries and secondaries have been turned into academies as a result. The idea behind the “coasting” category was to shine the spotlight on schools with good results that masked a failure to stretch their pupils - a typical example being a complacent school with a high-ability intake.

The Department for Education set out the criteria for picking out such schools in 2015, and warned: “Those that cannot improve will be turned into academies under the leadership of our expert school sponsors.”

It was the latter threat that excited the suspicions of teachers’ leaders. Chris Keates, general secretary of he NASUWT teaching union, accused Nicky Morgan - who was education secretary at the time - of “selecting criteria to define ‘coasting’ schools to maximise the opportunity for extending academisation,” while Kevin Courtney, then of the NUT teaching union, denounced it as “an attack on state comprehensive education and a further step towards privatisation”.

In November 2016, the DfE announced that 804 schools were likely to be classed as “coasting”. It said it “expects that only in a small minority of cases will regional schools commissioners (RSCs) direct a coasting maintained school to become a sponsored academy or move a coasting academy to a new trust”.

A Tes analysis of information obtained using the Freedom of Information Act has revealed that even this more modest scale of academisation has not come to pass.

The DfE lists six options open to RSCs. They could either take no further action; provide “some additional support and challenge”; require a maintained school to take specific action; appoint additional governors or an interim executive board; convert it into a sponsored academy, or issue a termination warning notice to an academy.

No further action

But of the 756 schools and academies that were ultimately branded as “coasting” and have not since closed, more than half (51 per cent) were told no further action was needed, and 49 per cent were told they needed some extra support.

In only one case did RSCs use any of their other powers: a termination warning notice was issued to the Basildon Upper Academy.

Far from all coasting secondary schools being turned into academies, none were converted. The same applies to primary schools.

Why has a policy that was launched with such fanfare not led to the expected action?

It may be that the “coasting” criteria did not identify any schools that needed anything more than some extra support.

But some believe the explanation is more complex, citing factors such as changing government attitudes, a shortage of strong sponsors, and a lack of capacity at the DfE.

Matthew Wolton, a partner specialising in academies at law firm Knights, believes that the “coasting” schools agenda involved “biting off more than you could chew”. For him, RSCs have more pressing priorities than trying to academise “coasting” schools.

“If they had sorted out all their inadequate schools and you had RSCs sitting on their hands saying ‘we don’t have anything to do’, I could see RSCs tackling this,” he adds.

He also points to changing priorities in the DfE itself. The concept of “coasting” schools was born in the era when blanket academisation was on the cards, but now, “the intention is to do it by encouragement rather than being forced to”.

And for Geoff Barton, general secretary of the Association of School and College Leaders, the fact that coasting schools have not been forced to convert could be a sign of changing attitudes to school improvement at the DfE, allowing schools more time to “put their houses in order”. “It might be a sign of a mood change in the department that there’s no quick-hit solution,” he says.

The DfE data reveals that among “coasting” primaries, 54 per cent of academies and 55 per cent of non-academies were told that no further action was needed. In the secondary sector, non-academies were more likely to be told they needed support: 57 per cent, compared to 52 per cent of academies.

There are also large regional variations, echoing concerns from union leaders about inconsistencies between the approaches taken by different RSCs.

In the East Midlands and Humber region, 77 per cent of primaries were told no further action was needed, while in the North the figure was 23 per cent.

And among secondary schools, 72 per cent in the South East and South London were told they need do nothing, while in Lancashire and West Yorkshire, the figure was 14 per cent.

Becky Allen, director of Education Datalab, believes there are three possible explanations: genuine differences in the school performance in different areas, RSCs recognising they have different capacity to help coasting schools, or it could be “completely arbitrary”.

So if RSCs are not using most of the tools they have been given to improve coasting schools, does the label serve any purpose?

Some, like Allen, question whether the technical definition succeeds in picking out the schools most people think of as “coasting”, but Wolton believes it can still be a force for good.

“If you are a school labelled as ‘coasting’, the positive effect is it will probably act as an incentive to say ‘we don’t like this, we will do what we can to avoid that label’,” he says.

“If you look overall at whether it has challenged schools in that category to improve, I think it’s likely.”

A DfE spokesperson said: “RSCs have been working closely with schools that met the coasting definition in January 2017 to ensure that support is available to secure improvements. We have been clear that the purpose of the coasting definition is to identify schools that may need support, and that more formal intervention, such as becoming an academy, was likely to happen in only a small minority of cases. The data reflects this, and demonstrates the hard work that RSCs are already doing to support many of these schools.”