PPS 21 Sustainable Development in the Countryside·Page 41·5.66
Design - Form and Proportion
The form and proportions of new buildings are critical to their visual impact on the landscape. Planning permission will be refused if the scale, form or massing would make the building dominant or incongruous in the local landscape.
The form and proportions of a new building are key elements in the design and strongly influence its visual impact on the landscape. If form and proportion are wrong, then little can be done with any other features to mitigate the impact of a poor design. Where the scale, form or massing of a building would make it dominant or incongruous in the local landscape planning permission will be refused.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/PPS 21 - Sustainable Development in the Countryside.pdf