Executive Summary 

Pupils with special educational needs and disabilities (SEND) are not evenly distributed across England’s mainstream schools. Instead, they are increasingly concentrated in a subset of schools. This matters because, as we report below, while a concentration of SEND pupils can build expertise and inclusive culture, it can also create pressure that many schools describe as difficult to sustain. It also matters for the Schools White Paper1, Every Child Achieving and Thriving, which expects every local mainstream school to meet more need: that ambition will be hard to realise if responsibility for SEND continues to cluster in a minority of settings. 

Drawing on national pupil data, a nationally representative survey of 800 special educational needs co-ordinators (SENCOs) and senior school leaders, and in-depth interviews with high-SEND case study schools, comparison schools, parents and local authorities (LAs), this report builds on our earlier scene-setting report, High-SEND schools: Understanding the uneven distribution of pupils with SEND across England’s mainstream schools. It explores why pupils with SEND cluster in certain schools and what this means for schools, pupils and families. 

What we found 

• SEND prevalence has risen steadily over the last decade: By 2024/25, more than 1.7 million pupils (around one in five) were identified with SEND in England’s school system. This reflects an increase over the last decade (from 14.4 per cent in 2015/16 to 19.5 per cent in 2024/25) and includes both pupils receiving SEN Support (the majority) and those with Education, Health and Care Plans (EHCPs) (around 0.4 million), who have seen the steepest increase, almost doubling in number over the period. Rising prevalence matters because it increases the likelihood that every school will need to meet a wider range of need, making the distribution of SEND across schools more consequential for capacity, sustainability and equity. 

  
  

• Pupils with SEND are unevenly distributed across mainstream schools and that unevenness is growing. In 2024/25, primary schools in the highest EHCP-rate quartile had around six times as many pupils with EHCPs as those in the lowest quartile (with a fivefold difference in secondary schools). Differences are also evident when we look at ‘any SEND’ (EHCP or SEN Support): primary and secondary schools in the highest any-SEND quartile have more than double the proportion of pupils identified with SEND compared to those in the lowest quartile (29 per cent vs 11 per cent in primaries; 26 per cent vs 10 per cent in secondaries). 

  
  

• The concentration of pupils with SEND appears to be driven by a structural steering effect: pupils are pulled towards certain schools with reputations for and expertise in inclusion and pushed towards them when capacity in other schools is constrained. This is reinforced by variation in school practices, with some schools less willing to develop a reputation for inclusion or actively discouraging admission of pupils with SEND—whether due to capacity pressures or concerns about performance measures. 

  
  

• Pull factors are rooted in school-level ethos and reputation. Inclusive schools become known locally as places that “will make it work”, shaping parental choice, professional advice and LA placement decisions. Our case study evidence suggests that the schools that sustain