Special educational needs campaigners have called for a commissioner to take over the running of a “chaotic” council service.
Campaign for Change (SEND Suffolk) claims hundreds of children are waiting for suitable full-time education.
The group met with the Department for Education (DfE), which said it would scrutinise Suffolk County Council.
The council – which has had to compensate SEND families for failings – said it was overhauling the service.
Campaigner Alex’s five-year-old son son Seb has autism and needs one-to-one support.
He is now in reception at a specialist school in Essex, but the process took two years, a tribunal and a complaint to the ombudsman.
“What we see with my family, and the hundreds of other families we speak to is that the council, in order to avoid this expensive provision, engages in any delaying tactics they can,” he told the BBC.
“A fine from the ombudsman of a few thousand or a few hundred pounds is nothing compared with the cost of the special provision that is required.”
Following a Freedom of Information (FOI) request in July, the campaign group found at least 254 children in Suffolk only had part-time schooling, 126 had been excluded and 104 had not been attending school.
Alex told the Local Democracy Reporting Service officials were “shocked” with the evidence they presented especially around children out of school, data quality and control of finances.
“It was clear that Suffolk County Council has hidden the true extent of the chaos and failure within its SEND system from them,” he said.
“They promised to take up these issues directly with the senior leadership at the council.
“We hope that any proper investigation will show that leadership change is required and we will be writing to the secretary of state again to demand his intervention.”
The DfE said: “We are working closely with Suffolk to ensure their plans for improving their SEND services lead to positive changes, so all children get a high-quality education regardless of need.
“We are confident that leaders in Suffolk are taking these concerns seriously and have plans in place to address them, including substantial new investment – but we will not hesitate to take further action to drive improvement if necessary.”
Campaign for Change (SEND Suffolk) is due to meet with the DfE again in the autumn.
The council formed an action plan last year to address concerns in SEND services after a report by peers in Lincolnshire exposed a series of failings.
“We are absolutely committed to improving SEND provision for children and young people in Suffolk and will not be knocked off-course,” it told the BBC.
It would not give updated figures relating to the FOI from last summer.