PPS 21 Sustainable Development in the Countryside·Page 32·5.35, 5.36
Justification: Design Limitations and Temporary Solutions
Residential caravans and mobile homes have limited potential for landscape integration due to their design and finishes, so permanent siting in the countryside is not permitted. However, temporary caravans or mobile homes can be a sensible solution for meeting residential accommodation needs in exceptional circumstances.
The design and finishes of a residential caravan or mobile home limits its potential for integration into the landscape. For this reason, planning permission will not be granted for a permanently sited residential caravan or mobile home in the countryside. It is accepted however, that in exceptional circumstances, a caravan or mobile home can be a sensible temporary solution, to meeting the need for residential accommodation in the countryside.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/PPS 21 - Sustainable Development in the Countryside.pdf