Severalls Hospital in Colchester, Essex, United Kingdom was a psychiatric hospital built in 1910 to the design of architect Frank Whitmore. It opened in May 1913. The 300-acre (1.2 km2) site housed some 2000 patients and was based on the “Echelon plan” – a specific arrangement of wards, offices and services within easy reach of each other by a network of interconnecting corridors. This meant that staff were able to operate around the site without the need to go outside in bad weather. Unlike modern British hospitals, patients in Severalls were separated according to their gender. Villas were constructed around the main hospital building as accommodation blocks between 1910 and 1935. Most of the buildings are in the Queen Anne style, with few architectural embellishments, typical of the Edwardian period. The most ornate buildings are the Administration Building, Larch House and Severalls House (originally the Medical Superintendent’s residence).