PPS 12 Housing in Settlements·Page 18·36
Identification of Land Beyond Urban Footprint
Land identification for housing beyond a settlement's urban footprint must be justified and reasonable, calculated as the residual after accounting for urban capacity, windfall allowance, and already constructed or committed dwellings.
It is not expected that every site identified will satisfy all of the above criteria, however, the approach taken must be both reasonable and justifiable. The requirement for identification of further land beyond the urban footprint in a settlement will be the residual after taking account of the urban capacity yield, windfall allowance and dwellings already constructed or committed.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/PPS 12 - Housing in Settlements.pdf