The headteacher behind plans for a controversial new middle school in Bury St Edmunds has hit back at critics, claiming any “surplus” places would be the fault of Suffolk County Council, not her trust.

Headteachers from 16 schools in the Bury area yesterday released an open letter to education minister Nicky Morgan claiming the government’s decision to allow the extra middle phase school for nine to 13-year-olds would harm children’s education.

However, Vicky Neale, lead headteacher of the All Through Trust and head of County Upper School, said its plans were simply responding to ever-increasing demand from parents for their schools and the three-tier model.

“If there are any surplus places, we have not created them,” she said. “That is down to Suffolk County Council; they have been fully aware of us and in fact supported the creation of the trust before the SOR (School Organisational Review) [two-tier] plans had started.”

The All Through Trust runs three primary and two middle schools in the Bury area, along with the ‘outstanding’ Ofsted-rated County Upper School.

Mrs Neale continued: “We have 900 houses being built at Fornham All Saints, which is traditionally the catchment of County Upper School – it is not as if there is not going to be any growth.

“The All Through model is clearly in demand, and we are responding to that demand. We bring extra choice for parents and by expanding our middle phase we will be able to accommodate the demand.”

The trust has been given permission by the Department for Education (DfE) to create a new middle school campus, which will be combined with a new secondary phase technology academy providing vocational education for 13 to 18-year-olds.

Both schools have been allowed under the Conservative government’s flagship free schools programme.

Mrs Neale said the 16 heads of the Bury Schools Partnership schools should be supporting them and looking forward to the opportunities an investment of £20million in the town’s education would bring.

“The technological academy will be the first in the country,” she said. “It was a big part of the Queen’s speech, providing vocational education for pupils who are not suited to academic subjects. This is a chance for Bury to be at the forefront of a new type of education.”

Sue Herriot, Guildhall Feoffment Primary headteacher and chairman of the schools partnership, said the plans would create a surplus of 400 places in town, disrupting years of planning for the move from three-tier to two-tier.

Suffolk County Council cabinet member for education Gordon Jones said they shared the concerns of the Bury Schools Partnership and confirmed they were exploring a legal challenge to stop the free-school bid.

The All Through Trust was created in 2011, but the county council says it was not aware of plans for expansion at middle school level until the application was granted by the DfE.

They did not support the bid for the secondary technical college.