Mitford Autism Unit is the first building in the UK designed specifically for adults with severely complex autistic spectrum disorders, marking a crucial step forward in the NHS’s treatment of autism. Having a facility solely dedicated to treating this disorder in adulthood provides it with much needed legitimacy, and helps to combat its associated stigma. The building provides care for up to 15 adults, in single and shared flats within four ‘fingers’ of accommodation. This pioneering move was rigorously developed with the client, including design innovations particular to the treatment of autism. Academic research indicates that a strong correlation exists between positive outcomes for people with autism and their environments, and that the condition is exacerbated by environments that greatly stimulate the senses. In order to negate this, we closed off certain areas to reduce visual stimuli, used secret doors and hidden cupboards, among other design techniques. Its design gives particular attention to the graduation from public to private space, with the vulnerability of each patient kept in mind. The thresholds from each flat to the circulation space, and the progress from this space to shared therapy spaces, are all carefully considered to avoid conflict with fellow patients. Wide, organically-shaped circulation spaces encourage movement but offer a measure of privacy and ‘safe’ window seats. All the flats are oriented to the east for a comfortable internal environment, with direct access to the private gardens to support the therapeutic needs of individuals. The ‘fingers’ of the accommodation are linked at their southern end by a band of shared spaces. After only a few months of its opening, the building and clinical environment has enabled improved care provision and is having a hugely positive impact on its patients.