Residential gardens are contained within the definition of previously-developed land in Annex B of Planning Policy Statement 3 (PPS3). However, paragraph 43 of PPS 3 says that local authorities can, when deciding the priority for the location of new housing, set out in their local development framework the contributions expected from different categories of previously-developed land. This could include residential gardens. If garden development is a particular issue for an authority, then they could also introduce a plan policy on development in gardens which, for example, could set out the circumstances and type of development that would or would not be acceptable.
On the 2 April the Government announced, via a response to a parliamentary question from the hon. Member for Sutton and Cheam, a review into the evidence on the extent and impact of housing development on garden land in order to establish whether there was a genuine problem. Further details can be found at: