The Warnock (1978) and HM Government (1981) were influential in effecting change from a stigmatising medical model of disability to a nuanced model of SEN and continuum of provision (Webster, 2019). However, the nebulous definition of SEN and context-specific framework meant the school-aged SEN populace increased from 1.8 to 20% overnight (Rutter et al., 1970), a figure which still informs SEN policy despite being based on a statistical artefact. Over the next two decades, the simultaneous pursuit of educational standards, inclusion, and equity led to a quasi-market system of school performance measures, school diversity and parental choice (Norwich and Black, 2015; Rayner, 2017). ‘Catch-all’ categories of high-incidence SEN (e.g., MLD: moderate learning difficulties; BESD: behaviour, emotional and social difficulties) provided a perverse incentive for schools to explain poor performance in league tables, contributing to political angst around unsustainable growth of the SEN populace (Squires, 2012; Rayner, 2017; Davies, 2019). An imperative to raise educational standards in poorly performing secondary schools led to the introduction of autonomous state-funded academies and a rigorous school inspection framework (Tomlinson, 2012). However, the performance-driven academy model brought a commercial ethos, ‘managerial paradigm’ and a lack of common values (Heilbronn, 2016), while pupils with SEN were further disadvantaged as schools grappled with complex needs that were beyond their expertise, capacity and resources (Tomlinson, 2010; Ekins et al., 2016; Kerr and Ainscow, 2017).

Warnock (2008) deplored the legacy of the eponymous report that had created a flawed SEN system and ideological tension between choice, educational standards and equity (Lamb, 2009; Ofsted, 2010; Norwich, 2014; Lindsay, 2018). Pupils with SEN were at increased risk of adverse psychosocial and economic outcomes, creating a socioeconomic imperative to enhance provision (Blatchford and Webster, 2018). In response, the UK government introduced a new Special Educational Needs and Disabilities Code of Practice (SEND: Department for Education and Department of Health, 2015), reformed examinations, a more nuanced performance measure and the requirement for all young people to be in education or training until their 18^th birthday. Under the new legislation, financial and strategic decision-making would be devolved to Local Authorities and children and parents would have greater agency over decision-making. Most pupils’ needs would be met in mainstream schools as part of the usual curriculum (SEN Support), whereas pupils with more complex SEN would have their needs formally assessed and additional support set out in a statutory ‘education, health and care plan’ (EHCP). Whilst this endorsed the international agenda of high-quality inclusive education (UNESCO, 1994), the reforms were not evidence-based and vision did not reconcile with practice (Shaw et al., 2016; Webster and Blatchford, 2017; Baird et al., 2019; Timpson, 2019), as explored next.

Under the new ‘Code’, Local Authorities effectively became responsible for a whole-community education-improvement programme and schools and colleges sought to navigate new SEN policies and procedures, reformed examinations and performance measures under a more rigorous inspection framework. Consequently, colleges withdrew courses popular amongst pupils with SEN who typically perform significantly worse across all performance measures (Burgess et al., 2017; Rayner, 2017; Department for Education, 2018, 2019; Liu et al., 2020), while schools requested vastly increased numbers of EHCPs for low-attaining pupils who are less likely to succeed in a performativity culture (Blatchford and Webster, 2018; Lindsay, 2018; Baird et al., 2019; Department for Education, 2019; Timpson, 2019). Together with a lack of guidance, inconsistent procedures, and financial constraints, this led to variation in SEN prevalence and provision between and within Local Authorities (Lindsay and Strand, 2016; Shaw et al., 2016; Department for Education, 2019).

Furthermore, less scrupulous academies engaged in covert selection procedures (Burgess et al., 2017; Rayner, 2017; Department for Education, 2018, 2019; Liu et al., 2020) and ‘off-rolling’ became a popular school-improvement tool as growing numbers of Year 11 pupils with social, emotional and mental health (SEMH) difficulties found themselves in alternative provision with only a 10% chance of being reintegrated into mainstream settings (Squires et al., 2012; Department for Education, 2018, 2019; Timpson, 2019). One Local Authority suggested alternative provision had become a de facto special school as pupils with high-incidence SEN were effectively erased from mainstream settings. Indeed, the ‘Code’ (Department for Education and Department of Health, 2015) was described as an ‘empty framework’ (Allan and Youdell, 2017) which caused a succession of ‘ghostings’ (Deleuze and Guattari, 1987). Added to this, members of the ‘corporation’ (Deleuze and Guattari, 1987) had vested interests in a growing client base, contributing to an expanding SEN industry with vested interests in SEN diagnosis (Ecclestone and Hayes, 2008). For instance, the patenting company of the psychotropic drug, Ritalin, made $464 million in 2010 (Tomlinson, 2012), and the British Dyslexia Association (2017) reported £58,000 in income from Education Conferences in 2017. Yet, unlike in traditional industry growth is a negative trait and supply and demand must be carefully controlled, as the ‘back-to-school’ season should increase revenue in stationery rather than medication (Ecclestone and Hayes, 2008; Tomlinson, 2012; Harwood and Allan, 2014).

Summarily, the simultaneous pursuit of educational standards, inclusion, and equity created a fragmented education system and a SEN system that was unfit for purpose (Webster and Blatchford, 2019). Ultimately, a divisive ‘corporation’ (Deleuze and Guattari, 1987) comprising Local Authorities, multi-agency professionals, businesses, voluntary organisations and parents had been established, all of whom had vested interests in SEN diagnosis. Moreover, the most vulnerable pupils were further disadvantaged, as social isolation and feelings of poor self-belief intensified (Squires et al., 2012; Lindsay and Strand, 2016; Rayner, 2017; Department for Education, 2019) and unmet needs ‘haunted’ the near future (Deleuze and Guattari, 1987). Together, this highlights how SEN prevalence can be an artefact of complex interactions between and within whole-community agendas, leading to the claim that SEN prevalence increases when resources are linked with SEN diagnosis (Tomlinson, 2010, 2012; Lindsay, 2018). Next, Gallant’s (2011) discourse on pupil disengagement provides a useful framework to explore how complex interactions between and within school contextual factors increase SEN prevalence.

Although it has been argued that SEN are entirely socially constructed (Prince and Hadwin, 2013), there is growing support for a social-medical model of disability, where pupils’ learning and behaviour difficulties are artefacts of complex interactions between physiological, environmental and social factors (Harwood and Allan, 2014; Ekins et al., 2016; Blatchford and Webster, 2018; Galloway, 2019). The literature shows how changes to school organisation, driven by hegemonic socio-political and cultural rhetoric and the need to seek cheap fixes to compensate for systemic failures, have affected pupils’ interpersonal experiences and engagement with the learning process (Lindsay and Strand, 2016; Perry, 2016; Shaw et al., 2016; Webster and Blatchford, 2017, 2019; Black, 2019; Mazenod et al., 2019). For instance, class sizes in the UK are relatively large due to limited resources, which presents challenges for the teacher in terms of maintaining an effective learning environment (Blatchford and Webster, 2018). Furthermore, schools have been incentivised to ‘teach to the test’ to raise attainment, resulting in a dry and uninspiring curriculum that is irrelevant to pupils’ experiences (Squires et al., 2012; Menzies and Baars, 2015; Kerr and Ainscow, 2017), which causes disengagement from the learning process (Gallant, 2011). This typically manifests as externalising behaviour (e.g., aggression) in boys and internalising behaviour (e.g., anxiety, depression) in girls, which can incentivise schools and teachers to seek SEN diagnosis (Strand, 2014; Galloway, 2019).

Moreover, strategies such as attainment-based grouping or ‘setting’ have been customised and teaching assistants (TAs) have become a central feature of the education of pupils in low-attaining groups (Blatchford and Webster, 2018; Black, 2019). While the rationale ostensibly seems to be to support struggling pupils and narrow the achievement gap, these strategies are believed to perpetuate inequitable and socially segregationist practices and outcomes, as pupils experience non-specialist teachers, restricted curricula and limited social interaction (Blatchford and Webster, 2018; Black, 2019; Mazenod et al., 2019). In turn, this can lead to an absence of school connectedness and reciprocal peer relationships which has been strongly associated with adverse psychosocial and behavioural outcomes and can be misinterpreted as SEN (Sammons et al., 2012; Squires, 2012; Prince and Hadwin, 2013; Menzies and Baars, 2015).

In sum, the literature highlights how complex interactions between and within school contextual factors can artificially construct learning and behaviour difficulties, contributing to SEN overidentification. However, factors beyond the school gates also influence SEN diagnosis, as discussed next.

Although contentious, research suggests that socioeconomic and cultural factors which stem from the home environment contribute to SEN overidentification (Department for Education and Department of Health, 2015; Lindsay and Strand, 2016; Shaw et al., 2016; Oldfield et al., 2017; Black, 2019; Galloway, 2019; Mazenod et al., 2019; Timpson, 2019). For instance, Department for Education (2022) data show that: (1) pupils from low socioeconomic backgrounds are more likely to be diagnosed with SEN than their less-disadvantaged peers; (2) children in lone parent families are more likely to have SEN (12%) compared with children in couple families (7%); (3) looked after children (LAC) who have been in the care of the Local Authority continuously for 12 months are more likely to be diagnosed with SEN (56.2%) compared with the overall SEN populace (15.8%).

Explaining this, researchers suggest that learning and behaviour difficulties in school stem from a lack of core knowledge (Menzies and Baars, 2015) and reading experience (Huettig et al., 2018), as well as an exposure to negative social and cultural influences, such as unstable households and familial stress (Oldfield et al., 2017). Furthermore, scholars highlight how ‘troubled families’ discourse and ‘dependency culture’ rhetoric ensure a negative culture of values and behaviours is perpetuated through generations (Mazenod et al., 2019), incentivising schools and low socioeconomic families to seek SEN diagnosis for low-attaining children (Shaw et al., 2016; Baird et al., 2019).

Moreover, evidence suggests ethnicity plays a part in the likelihood of a child being diagnosed with SEN (Lindsay and Strand, 2016; Shaw et al., 2016; Tomlinson, 2016). For instance, Lindsay and Strand (2016) found that all Asian-heritage groups were overrepresented for speech, language, and communication needs (SLCN) compared to their White British counterparts, which varies in disproportionality between Local Authorities. Furthermore, teachers’ perceptions of pupils’ achievement potential have been found to relate systematically to ethnicity (Strand, 2012), with data showing that travellers of Irish heritage (5.7%) and Black Caribbean pupils (5.4%) have the highest percentage of EHCPs (Department for Education, 2022). Indeed, Strand’s (2014) ethnographic study reported that Black Caribbean and White British pupils from low socioeconomic families are most affected by the hidden curriculum.

Taken together, the literature demonstrates how particular socioeconomic and cultural identity markers seem to make SEN diagnosis inevitable when intertwined with schools’ and teachers’ interpretations of pupils’ learning and behaviour difficulties (Harwood and Allan, 2014). However, certain within-child factors have been identified as risk markers (Squires et al., 2013; Black, 2019; Kauffman and Anastasiou, 2019), as examined next.

Since the Warnock (1978), the simultaneous pursuit of educational standards, inclusion and equity has meant all pupils should be educated in mainstream schools, irrespective of academic attainment. Furthermore, all pupils should achieve a particular level by the end of each Key Stage (Squires, 2012). The literature demonstrates that interactions between these distal factors and certain within-child risk markers increase the likelihood of SEN diagnosis and contribute to SEN overidentification (Squires et al., 2013; Lindsay and Strand, 2016).

First, scholars highlight how natural development is not considered when measuring pupils’ progress, meaning those who are not making expected progress toward politically defined targets can be misdiagnosed with SEN (Squires, 2012; Lindsay and Strand, 2016). For instance, typically developing summer-born pupils are identified with SLCN more frequently than their autumn-born counterparts because they have not developed the physical, emotional and cognitive skills needed for Key Stage assessments (Martin et al., 2004; Lindsay and Strand, 2016). Indeed, Squires et al. (2013) reported that children born in August are 1.5 times more likely have conduct problems and be diagnosed with SEN than their peers who are born in September, which represents the start of the school year in the UK. This putative month-of-birth effect becomes more pronounced through adolescence when hormonal changes exacerbate SEMH difficulties (Squires et al., 2012, 2013; Department for Education, 2017). Specifically, the number of pupils with an EHCP peaks at age 15 (Department for Education, 2019), leading to the claim that school performance measures and ‘catch-all’ categories of SEN have incentivised schools to seek diagnosis for pupils who are unlikely to meet politically defined targets by the end of Key Stage 4 (Squires et al., 2013).

Gender is also an important factor in SEN overidentification, with recent national data (Department for Education, 2022) showing that more boys receive SEN support and have an EHCP (15.4 and 5.6% respectively) than girls (9.2 and 2.2%). Whilst Boaler’s (1997) seminal study attributes this to girls’ capacity to adapt to teaching approaches they dislike, research shows that some cognitive processes mature more slowly in boys and they are more likely to be affected by the hidden curriculum (Hehir et al., 2016; Black, 2019; Timpson, 2019). For instance, boys are twice as likely to be diagnosed with SLCN than girls (Lindsay and Strand, 2016), which has been associated with an increased likelihood of displaying conduct problems and SEN diagnosis (Squires et al., 2013).

Summarily, a child’s interaction with a series of interdependent environmental systems through the lifespan shapes their development and certain risk markers increase the likelihood of SEN diagnosis. Indeed, within-child factors provide some explanation for: (1) variation in SEN prevalence between and within Local Authorities; (2) SEMH being a high-incidence ‘catch-all’ category of SEN; (3) poverty not having the same impact on all ethnic-minority groups; (4) increased numbers of boys being diagnosed with SEN (Tomlinson, 2010; Squires et al., 2012, 2013; Lindsay and Strand, 2016).