Around 50% of children with autism spectrum disorder (ASD) have at least one anxiety disorder[2]. In a clinical setting, anxiety-related symptoms are among the most common presenting problems for school-age children and adolescents with ASD[3]. Anxiety may exacerbate the social impairments associated with ASD and result in young people avoiding situations they find stressful. Graduated exposure is identified as the key therapeutic mechanism in evidence-based treatments for specific fears and phobias[4], but may require adaptation for individuals with ASD. For example, graduated exposure may begin with imaginal desensitisation; however, individuals with ASD have difficulties with imagination, and find producing and controlling imaginal scenes difficult. In addition, many individuals with ASD find explaining their internal emotional states challenging. One solution for people with ASD is the use of virtual reality environments (VREs). We have developed a partnership with staff at the ‘Blue Room’ VRE developed by a County Durham based company, Third Eye. In the ‘immersive’ Blue Room we used computer generated images of the specific phobia/fear environment to reproduce the situation that the child finds difficult (e.g. going into a shop to buy something). Therapeutic work (improved understanding of emotions, coping strategies) was delivered simultaneously by an assistant psychologist within the Blue Room itself. A manual for the steps in treatment has been created. Our development study with volunteer children showed this treatment allowed young people with ASD to effectively manage their phobia/fear. Eight of nine participants showed real life functional improvements and reduction in scores on anxiety scales after four 20-minute VRE 'Blue Room' sessions. For example, one child in our development study had a fear of crowded buses. His family did not have a car and frequently waited long periods for an uncrowded bus to arrive. After attending the Blue Room treatment sessions, the child is able to get onto crowded buses – this has improved his everyday life, and that of his parents and siblings. Aims We will investigate the feasibility of recruiting 32 young people from clinical services, and ascertain whether children with ASD presenting for treatment for specific phobia/fear in the NHS improve after being randomised to immediate VRE treatment, or treatment delayed for 6 months. We will also investigate the feasibility of training different NHS therapists to deliver the VRE-based treatment. As part of feasibility work, a range of outcome measures will be assessed including functional improvement and confidence in real life situations, scores on the Spence Children’s Anxiety Scale and the FEAR survey, and a measure of the child’s wider opportunities using Children’s Assessment of Participation and Enjoyment. Change in levels of anxiety and fear will be related to initial levels of anxiety. We will interview parents and the child at the end of the study to assess the acceptability of the intervention. We will explore economic outcome measures related to clinical utility, including using a measure of health outcome, investigating what services young people use, and what need for service use the intervention might change. This study will establish what steps will be necessary to collect the appropriate costs for an economic evaluation in a randomised trial, or clinical utility trial. Potential Impact Reducing specific phobia/fear in children with ASD has the potential to decrease anxiety and distress, and improve everyday life and participation in society for the child. Parents and siblings would also benefit through increased opportunities to participate in usual activities. Health economic outcomes will show the potential value in NHS and societal savings. If NHS children can be successfully recruited, and local therapists deliver the treatment effectively, this treatment could be commissioned by NHS services, benefitting children and families.