The Newbury tests and when a condition is unlawful
A planning condition can satisfy every policy test in guidance and still be unlawful. The Newbury tests are the three that decide validity.
The Newbury tests are the legal conditions a planning condition has to satisfy to be valid, and they are three, not six. A condition must be imposed for a planning purpose and not for an ulterior one, it must fairly and reasonably relate to the development permitted, and it must not be so unreasonable that no reasonable authority could have imposed it. Those tests come from the House of Lords decision in Newbury District Council v Secretary of State for the Environment, and they sit alongside, rather than inside, the policy tests in national guidance. A condition can satisfy every policy test and still be unlawful.
Where the tests come from
The power to impose conditions is in sections 70 and 72 of the Town and Country Planning Act 1990, and it is expressed broadly: the authority may grant permission subject to such conditions as it thinks fit. The courts have read that power as constrained by the three tests, which restate principles developed in earlier cases and settle them in a form practitioners still use.
The distinction between the legal tests and the policy tests matters when you are arguing with a case officer. The policy tests in guidance are what the authority should apply as a matter of good practice, and an appeal inspector will readily strike out a condition that fails them. The Newbury tests are what makes a condition lawful or unlawful, and they are the ones a court will apply on a challenge.
Planning purpose and the ulterior motive
The first test excludes conditions imposed to achieve something the planning system is not for. A condition requiring a developer to make a payment to the authority for general purposes, or to grant rights over land to the council, or to employ local labour without a land use justification, is imposed for an ulterior purpose however desirable the outcome.
The practical test is whether the condition is directed at the use and development of land. Conditions controlling hours of operation, deliveries, external lighting and the design of a bin store are plainly within it. Conditions dictating who may occupy a building require a land use reason, and occupancy restrictions on rural workers' dwellings are upheld precisely because such a reason exists.
Fairly and reasonably related to the development
The second test is the one most often failed in practice. A condition must relate to the development permitted, not to some other activity of the applicant or some other part of their land.
The classic example is a condition requiring the developer to build a road across their land and give the public the right to use it, which the courts held to be unlawful because it required the applicant to give up rights in a way the authority could have achieved only by paying for it. The same logic catches a condition that requires works to an unrelated building, or that regulates an existing lawful use the application did not touch.
Two boundary cases are worth knowing. A condition can regulate the whole planning unit where the development affects it, so a condition restricting parking across a site is valid on an application for an extension that increases the demand. And a condition can require something to happen on other land where the applicant controls it and the requirement is related to the development.
Reasonableness and the Wednesbury overlay
The third test is a high bar. A condition is invalid only if no reasonable authority could have imposed it, which is a different question from whether the condition is unwise, burdensome or annoying.
Conditions have fallen under this head where compliance was impossible, where the condition would render the permission useless, and where the burden imposed was wholly disproportionate to the harm being addressed. A condition requiring a level of mitigation the development could never fund is the modern version, and it is usually resolved through a viability argument rather than a legal one. Our note on benchmark land value covers the ground that argument is run on.
Conditions that fail for uncertainty
A condition has to tell the reader what is required. One that cannot be understood, or that has no ascertainable meaning, is void for uncertainty, and the courts will strike it down rather than try to give it a workable reading.
The drafting failures that produce this are familiar. Conditions requiring something to be done "to the satisfaction of the local planning authority" without saying what is to be done. Conditions referring to a document that was never submitted or never identified. Conditions using a term with no settled meaning, such as a requirement that a building be "in keeping" without any reference point. And conditions that contradict another condition on the same permission.
Read every condition on a draft decision notice and ask a simple question of each: could a surveyor standing on the site, with only this notice, tell whether it had been complied with. If not, it needs redrafting before the notice is issued, which is a five-minute conversation, rather than afterwards, which is an application.
Conditions requiring works outside the site
Negative conditions preventing development until something happens on land outside the applicant's control are lawful and common, and they are usually called Grampian conditions after the case that established them. The earlier requirement that there be a reasonable prospect of the works being carried out within the life of the permission has been relaxed by later authority, so such a condition can be imposed even where the prospect is uncertain.
The distinction to hold onto is between a negative condition and a positive one. A condition saying no dwelling shall be occupied until a junction has been constructed is lawful. A condition saying the applicant shall construct a junction on land they do not control is not, because it requires something the applicant cannot lawfully do.
| Condition type | Lawful | Why |
|---|---|---|
| Negative Grampian condition | Yes | Restrains development rather than compelling works |
| Positive duty on third party land | No | Requires what the applicant cannot deliver |
| Condition requiring dedication of land | No | Achieves by condition what requires purchase |
| Occupancy restriction with a land use reason | Yes | Directed at the use of land |
Challenging a condition rather than the permission
Three routes exist and they carry different risks.
- An application under section 73 to vary or remove the condition, which leaves the original permission intact and produces a fresh permission with the condition altered if granted.
- An appeal under section 78 against the condition, which is effective but exposes the whole decision to reconsideration, because the inspector can deal with the application as if it had been made to them in the first instance.
- A challenge in the courts on the ground that the condition is unlawful, which is rare and normally worth doing only where the condition is fundamental and the permission would stand without it.
The first is the safe route in most cases, and it is the one to use where the objection is to the burden rather than to the legality. The third matters because a condition that is unlawful and fundamental can take the permission with it, which is not the outcome most applicants want.
Where the argument is about the timing of a plan rather than the terms of a condition, our note on prematurity covers the ground. For the documents a section 73 application needs, browse the report types by category.
This is general guidance, not legal advice, and you should take advice from a qualified lawyer before challenging a condition. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
What are the Newbury tests?
Three legal tests for the validity of a planning condition, from Newbury District Council v Secretary of State for the Environment. The condition must be imposed for a planning purpose and not an ulterior one, must fairly and reasonably relate to the development permitted, and must not be so unreasonable that no reasonable authority could have imposed it.
How do they differ from the policy tests in guidance?
The policy tests set out what an authority should do as good practice, and an inspector will strike out conditions that fail them. The Newbury tests decide whether a condition is lawful at all, and they are what a court applies on a challenge. A condition can pass every policy test and still be legally invalid.
Are Grampian conditions lawful?
Yes. A negative condition preventing development from proceeding until something happens on land outside the applicant's control is lawful, and later authority relaxed the earlier requirement that there be a reasonable prospect of the works happening. A positive condition that requires works on third party land is not lawful.
When is a condition void for uncertainty?
When it has no ascertainable meaning. Common causes are conditions requiring something to the satisfaction of the authority without saying what, references to documents never submitted or identified, terms with no settled meaning such as a requirement to be in keeping, and conditions that contradict another condition on the same permission.
Should I appeal a condition or apply under section 73?
Section 73 is usually safer, because the original permission survives and a fresh permission is issued with the condition altered if granted. A section 78 appeal against a condition exposes the whole decision to reconsideration, since the inspector may deal with the application as though it had been made to them.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.