PPS 21 Sustainable Development in the Countryside·Page 30·5.30
Justification – Establishment and Site-Specific Need
Non-agricultural businesses in the countryside must demonstrate a clear site-specific need for residential accommodation, not merely a general desire. The need must be essential for the business to function, beyond general preference.
Established non-agricultural business enterprises, located in the countryside, may require residential accommodation. The presence of such a business is not, of itself, sufficient justification to grant permission for someone to live on the site. Applicants must provide sufficient information to show that there is a site specific need which makes it essential for one of the firm's employees to live at the site of their work, as against a general desire for a dwelling in association with the business.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/PPS 21 - Sustainable Development in the Countryside.pdf