A survey of 1,246 teachers and school leaders across England by the National Foundation for Educational Research found that although 43 per cent of the sample of 143 academy leaders said autonomy had a positive effect, 30 per cent believed it had “no effect” and 18 per cent said it had a negative effect.

The survey suggested that only 27 per cent of all those - including teachers and leaders - who work in academies thought their autonomy had a positive impact in the classroom, while only 8 per cent of staff at non-academy schools saw academy autonomy as beneficial.

The polling was published ahead of a summit in New York hosted by the Sutton Trust and Carnegie Corporation of New York, which will look at international evidence on improving social mobility.

Autonomy over the curriculum

Of the teachers who believed that the effect of academy autonomy had been positive, most cited freedom on the curriculum (63 per cent) and control of resources (60 per cent).

Almost half (47 per cent) cited the benefits of more collaboration with other schools, and 50 per cent mentioned control over learning programmes. Senior leaders also cited freedom from local bureaucracy (51 per cent).

The Sutton Trust also gathered polling data from the US on the impact of school autonomy. A survey by YouGov of 501 public school teachers across the country found that 25 per cent felt that the autonomy given to charter schools (the US equivalent of academies) had a positive effect on the day-to-day life of classroom teachers, while 36 per cent said it had been negative and 20 per cent felt it had no effect.

Sir Peter Lampl, founder of the Sutton Trust and chairman of the Education Endowment Foundation, said the polling showed that school leaders were “sceptical about the benefits of their autonomy”.

“The focus should not be on school structures but on improving the quality of teaching in schools,” he said. “The evidence from work by the Sutton Trust and by the EEF shows overwhelmingly that improving quality of teaching is the key to boosting standards for all pupils and disadvantaged pupils, in particular.”

Forced academisation ‘doesn’t guarantee improvement’

Paul Whiteman, the general secretary of the NAHT heads’ union, said the research showed that “forcing a school to become an academy does not guarantee that everything will get better for pupils and staff”.

He added: “What matters most is that schools are properly funded and well resourced, with sufficient talented and well-supported teachers.”

The polling in the UK provided further evidence that the school funding crisis is beginning to bite.

Nearly three-quarters (74 per cent) of secondary school leaders said their schools had cut teachers over the past year, with a similar proportion saying the same about teaching assistants (74 per cent) and support staff (72 per cent).

Staff cuts were lower - but also on the rise - in primary schools, with 60 per cent cutting TAs and 24 per cent classroom teachers.

And one in three (34 per cent) of senior leaders reported that the pupil premium was being used to plug gaps in their budget, up from 30 per cent last year.

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