The Newbury Principles collectively refer to an urban planning guideline stating that decisions should be made based only on the planning considerations relevant to the current development, even if the consideration of ulterior purposes may lead to a greater public good. In practice, the principles are used as a test to verify the validity of conditions to be imposed by a planning authority.
Specifically, the decision of the House of Lords in Newbury District Council v Secretary of State for the Environment (1981) contains the following three principles when considering the reasonableness of imposing conditions on consents:
- It must be imposed for a planning purpose.
- It must fairly and reasonably relate to the development for which permission is being given.
- It must be reasonable.
In Australia, the Newbury principles are formally used only in the Land and Environment Court of New South Wales; therefore, the term is predominantly invoked for development consents only in that state. The Newbury test also remains in general application in the courts of New Zealand.