The National Union of Teachers is to notify De Warenne Academy, Ash Hill Academy and Don Valley Academy in Doncaster and to Melior Community Academy in Scunthorpe today.
All four schools are part of the School Partnership Trust Academies (SPTA) chain.
The union say the restructure will “result in the loss of teachers jobs and a narrowing of the curriculum”.
However SPTA said that pupils were being asked to take too many subjects which was leading to some of the worst results in the country at some of its academies.
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The academy chain also said that it was projected to lose £6.8m this year unless it made changes.
Emma Forrest NUT senior organiser said: “We believe that SPTA are rushing into this restructuring without properly engaging in consultation with trade unions or parents or the wider community. The removal of subjects such as business studies and ICT as well dance, drama and music will lead to a distorted and unbalanced curriculum which will have a detrimental impact on pupils education.”
However the SPTA has said that until now children at some of their schools have been doing too many subjects, leading to pressure to revise for a huge number of exams.
It said this was contributing to poor exam results.
A spokesman said: “School Partnership Trust Academies recognises the difficulties faced by some of its secondary academies.
“We have hard working and dedicated staff, who despite their diligence and professionalism, are in academies that have outcomes for young people that are
some of the worst in the country.
“This is mainly due to children studying large numbers of GCSEs and then being pressured to revise for a huge number of exams resulting in them achieving lots GCSEs all of poor quality.
“We believe that we should offer the same range of subjects but you should choose between eight to 12 subjects.
“There is a reason that these schools perform so poorly and it’s not the students or the staff to blame.”
On the finance they added: “The trust lost £3.2m last year and was projected to lose a further £6.8m this year because of the significant overstaffing which had never been addressed.”
“We have worked hard to reduce any redundancies to a handful and will continue to work to reduce this further in the coming months.”
SPTA is the biggest academy chain in Yorkshire responsible for more than 40 schools. It appointed a new chief executive, Paul Tarn, in March this year.
SPTA also began working with another major academy chain Outwood Grange Academies Trust, where Mr Tarn had previously been the deputy chief executive. Last year The Yorkshire Post revealed a Government schools commissioner had written to SPTA to warn them about standards in a third of their schools.
A spokesman for the trust suggested that poor exam results were linked to pupils taking too many exams, while the trust was projected to lose £6.8million this year “because of significant overstaffing which had never been addressed”.
He added:“We have worked hard to reduce any redundancies to a handful and will continue to work to reduce this further in the coming months.
“We started the consultation on restructure as soon as we could so that staff in these schools could apply for posts in the most intensive period of teacher recruitment, April and May.
He added: “In addition the trust has offered protection to teachers whose pay grade may change for three years and delayed the start until January 2017: this means that staff will not lose financially until January 2020 and we have offered to review pay structures in September 2019.
An SPTA spokesman, said staff were notified and consulted on the restructure as soon as was possible.
Earlier this year Ofsted wrote to SPTA bosses about a series of inspections at their schools. It found that the impact of the SPTA’s work in bringing about improvement where it is most needed had been too slow.
It also said that SPTA was having more of an impact at its primary academies than its secondary schools.
Sir Paul Edwards, SPTA’s previous chief executive, left his post at the end of last year.
The academy chain has grown from what was Garforth Community College in Leeds. It expanded during the coalition Government’s roll out of the academies programme.
In a letter seen by the Yorkshire Post last year, regional school commissioner Jennifer Bexon-Smith warned it had “grown relatively quickly” and had capacity issues as a result of this.