Every Suffolk school will be ‘good’ or ‘outstanding’ within 18 months, under ambitious plans to rapidly improve students’ results.

The changes would mean almost 80 schools – about 25% in the county – would have to raise their ‘requires improvement’ or ‘inadequate’ Ofsted grades, with no current ‘outstanding’ or ‘good’ schools worsening.

The plan released by Suffolk County Council follows an inspection by the education watchdog of how the authority supports schools after years of poor national league table results. In last month’s report Ofsted inspectors criticised the council for being “too slow” to act to help schools.

Now education bosses have released their plan of action, through flagship education programme Raising the Bar, in response to the inspection which also said “decisive improvements” had been made.

The main points of the council’s plan of action are: all schools to be ‘good’ or ‘outstanding’ by January 2017; no schools still rated by the council as ‘red’ – meaning significantly under-achieving (currently 88 schools have red ratings); help to ‘rapidly improve’ results for disadvantaged children; and pupils meeting or exceeding national exam averages in nursery, primary and secondary schools.

Lisa Chambers, cabinet member for education and skills, is confident of hitting the 2017 target.

“The recent Ofsted inspection endorsed the work we have been doing towards improving education outcomes for young people in Suffolk, through Raising the Bar,” she said.

“The report also outlined areas where more needs to be done to accelerate progress.

“We have developed a robust action plan following the inspection which will shape the next phase of Raising the Bar, making sure we focus on key areas for improvement, including having all schools in the county rated as ‘good’ or ‘outstanding’ by 2017 and further work to make sure disadvantaged young people in achieving the very best they can.”

A total of five primaries and six secondaries, academies or middle schools are rated as ‘inadequate’. A total of 55 primaries and 11 secondaries, academies or middles are classed as ‘requires improvement’.

One issue for the council could be that several of those inadequate schools are academies – run by a sponsor and not the authority.

An academy sponsor is responsible for its school and is held accountable by the Department for Education. But league tables include all of Suffolk’s state schools, with the council responsible for raising overall county standards.

Graham White, secretary of Suffolk National Union of Teachers, , described the plan as “incredibly ambitious”.

He said the key issue behind poor performance for disadvantaged pupils is poverty. He said progress would be slow unless that underlying cause was tackled.

“I have no problem with the target but it is incredibly ambitious and I think teachers, parents and pupils will say it’s really good aiming high but they may not be able to achieve it,” he said. “The authority has a plan of action to address concerns but my worry is that some of the ‘red’ rated schools will not be local authority schools, they will become academies which is not the right way forward. Academies have no real record of turning schools around.”

Andrew Cook, Ofsted’s regional director for the East of England, said the council’s plan would now be reviewed ahead of a reinspection in 2017.

On Friday, this newspaper revealed how senior councillors plan to spend £800,000 more on Raising the Bar. Almost £1million has already been invested since the scheme started in 2012.