Changes to special educational needs provision in England could be thwarted by “academic attainment at all costs” policies that prioritise exam results and punish inclusive schools, headteachers have said in response to a government consultation.

The Association of School and College Leaders said the government’s emphasis on academic goals conflicted with its measures designed to help mainstream schools accommodate more children with special educational needs and disabilities (Send).

The union said the adherence to “high-stakes” assessments, including a proposed test of year 8 reading, “all create perverse incentives for school and college leaders where they are penalised for any lower academic outcomes for some pupils with Send. This cannot be addressed with reform of Send in isolation.”

In its formal response to the schools white paper, the ASCL said: “Contrary to the strong focus on inclusion in the early chapters of the white paper, the ‘ambition’ section of the paper omits Send and broader outcomes and is still focused on academic attainment at all costs. This critical inconsistency will be the basis upon which the reforms will succeed or fail.

“If we want an education for all then that principle of ‘for all’ must apply to all areas of education policy.”

Margaret Mulholland, the union’s Send and inclusion specialist, said: “The government’s reforms have the potential to do a huge amount of good but they must help schools deliver them. Guidance must then be backed up by adequate staffing, funding, and time for preparation – including training where necessary.

“Without this, there is a serious risk that schools will be placed in an impossible position, relationships with parents will be damaged and children will be left without the support they need.”

Under the proposed changes, mainstream schools will be expected to have an “inclusion base” for children with special needs, but the ASCL said there was little detail on how the bases would operate.

“The inclusive base should not encompass rooms which host children excluded from classrooms on the basis of behaviour … Inclusion bases should not become holding pens, standalone units or exclusion by another name,” it said.

The Coram group of children’s charities responded to the consultation by warning against narrowing parents’ grounds for appeals to specialist Send tribunals.

“School complaints processes are not an adequate replacement for legally enforceable rights,” it said. “This is likely to cause significant tensions between schools and parents-carers, adding more stress on the school system and parents. It is also likely to result in more litigious action, such as judicial reviews of decisions.”

New research from the National Foundation for Educational Research (NFER) found that the changes could be hampered by the increasingly high concentration of pupils with Send within a small number of mainstream schools.

The study found a huge gap between mainstream schools with the least and most Send pupils: the lowest fifth averaged just 10% of pupils with Send while the highest fifth averaged 26%.

The NFER said “structural steering” meant families were attracted to schools with good reputations, while other schools discouraged pupils with Send from applying. The report quoted one school leader as saying: “We’ve always tried not to have a reputation for being good at Send so parents don’t tend to seek us out.”

Daniel Kebede, the general secretary of the National Education Union, said: “This report shows there is a clear case for a stronger role for local authority-controlled admissions, with oversight to ensure that placement decisions are made fairly and transparently.”