Numerous interventions have been identified by research as being effective in reducing the severity of some of the core impairments and challenging behaviours of young people with autistic spectrum disorders (ASDs) and learning difficulties. However, the literature cites significant disparity between what is demonstrated to be effective in supporting young people with ASD and challenging behaviour and the support young people and families actually receive in practice. Paper 1 examines the extent to which evidence-based practice translates into actual practice in special schools in the UK for young people with ASD, severe learning difficulties (SLD) and challenging behaviour. A questionnaire survey targeting 64 special schools in the Midlands was used in conjunction with a series of follow-up semi-structured interviews of school staff. The findings indicate that: 1) the ideal of eclectic provision is potentially undermined by a limited range of training received by staff in evidence-based approaches; 2) mechanisms for supporting staff emotional reactions are inconsistently implemented; 3) limited mechanisms exist for developing staff understandings of challenging behaviour. Furthermore, staff attributions regarding challenging behaviour are pivotal to the consistency and effectiveness of any support programme. Implications and future research directions are discussed.