The Newbury tests for a valid planning condition

The Newbury tests planning condition question comes up whenever a condition looks wrong rather than merely inconvenient. The House of Lords in Newbury District Council v Secretary of State for the Environment set out three requirements for a lawful condition: it must be imposed for a planning purpose and not 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. A condition failing any of the three is unlawful, which is a different and stronger objection than saying it is unnecessary.

The three limbs of the test

The first limb is about purpose. A condition must serve planning ends. A condition imposed to raise revenue, to assist another public body with a problem unrelated to the development, or to achieve something the authority wants for reasons outside the planning system fails on purpose alone, however reasonable it looks.

The second limb is about connection. The condition must fairly and reasonably relate to the development being permitted. That is why a condition on a single house extension requiring works to a junction half a mile away is vulnerable: the link is too remote. Scale matters to this limb. The same junction works attached to a 200-dwelling scheme that generates the problem would relate perfectly well.

The third limb is the familiar public law standard. A condition is unlawful if no reasonable authority could have imposed it, which is a high threshold deliberately. Disagreeing with a condition is not enough. Showing that it makes the permission unimplementable, or that it strips the owner of a right without compensation, can be.

Two points practitioners sometimes miss. The limbs are cumulative, so a condition must satisfy all three. And the power to impose conditions in section 70(1)(a) of the Town and Country Planning Act 1990 is expressed as "such conditions as they think fit", which sounds unlimited and is not, because the common law test and the policy tests both constrain it.

How the common law test sits with the six policy tests

National guidance adds six tests: conditions should be necessary, relevant to planning, relevant to the development to be permitted, enforceable, precise, and reasonable in all other respects.

The relationship between the two sets is often misunderstood. The policy tests are guidance, so breaching one makes a condition contrary to policy and a proper subject for appeal or variation. The Newbury limbs are law, so breaching one makes a condition invalid. A condition can satisfy all three legal limbs and still fail the policy tests, for example by being imprecise or unnecessary, and that is the normal situation in practice.

So the drafting of a challenge should separate them. Argue invalidity where the legal test is failed, and argue policy non-compliance where it is not. An appeal statement that runs both together as a single complaint of unreasonableness tends to get the weaker answer.

Conditions that fail for unreasonableness

Case law has struck down conditions in a handful of recognisable categories.

Conditions requiring the applicant to give up land or rights without compensation, such as a requirement to construct a road over the applicant's land and dedicate it for public use. The planning system has other mechanisms for that, and using a condition is an abuse of the power.

Conditions that nullify the permission, by making implementation impossible or by removing the benefit entirely. Where a condition has that effect on the land as a whole, the owner may also be looking at the mechanisms described for purchase notices where land cannot be reasonably used.

Conditions requiring a payment of money or the provision of a financial contribution. Planning obligations under section 106 exist for that purpose, and a condition cannot be used as a shortcut.

Conditions requiring something outside the applicant's control with no mechanism for achieving it, and conditions dependent on the agreement of a third party who is under no duty to agree.

Conditions that are so imprecise that nobody can say whether they have been complied with. These usually fail the policy tests on precision and enforceability rather than the legal test, but a condition requiring development to be carried out "to the satisfaction of the local planning authority" with no criteria is close to the line.

Conditions reaching outside the application site

Negatively worded conditions preventing development from starting until something happens elsewhere, usually called Grampian conditions after the case that established them, are lawful in principle. They do not require the applicant to do the off-site work. They simply prevent the development proceeding until it is done.

But the case law is permissive about them. National guidance is more cautious, advising that conditions requiring works on land outside the applicant's control should be used only where there are at least reasonable prospects of the action being performed within the time limit of the permission.

Three practical consequences.

1. Where the off-site work needs a highway agreement or a third party's land, establish the prospect of delivery before accepting the condition, because a permission conditioned on something that cannot happen is worthless.
2. Where an authority proposes an off-site condition that should properly be an obligation, say so. The distinction matters for enforceability and for the levy position.
3. Where the condition relates to construction effects rather than permanent works, a Construction Management Plan secured by condition is usually the better instrument, because it keeps the control on the applicant's own activity.

Severing an unlawful condition

Finding a condition unlawful does not automatically leave a clean permission behind. The question is whether the condition can be severed.

Where the condition is incidental, it can be struck out and the permission stands. Where it goes to the heart of the permission, so that the authority would not have granted consent without it, the permission falls with the condition. That is a real risk on schemes where an occupancy restriction, a phasing requirement or a highway trigger was the basis on which members were persuaded to approve.

The practical implication is uncomfortable. An applicant with a permission containing a condition they believe to be unlawful has to decide whether they would rather have the permission with the condition than no permission at all. In most cases the answer is yes, which is why section 73 is used far more often than invalidity arguments.

Challenging a condition

Four routes, with different risks.

An appeal under section 78 against the condition. The appeal is a re-determination, and the inspector deals with the application as if it had been made to them at first instance, so the whole permission is in play rather than just the condition. On a finely balanced approval, that is a real risk.

An application under section 73 to vary or remove the condition. This produces a new permission, subject to conditions the authority chooses, and the original permission survives if the application fails. It is the low-risk route and it is usually the right one. Note that section 73 cannot be used to extend a time limit for beginning development.

A non-material amendment under section 96A, for minor adjustments to a condition's wording where the effect really is immaterial.

Judicial review, where the condition is said to be unlawful and no other route gives an adequate remedy. The time limits are short, measured in weeks rather than months, and the court is reviewing the legality of the decision rather than its merits.

Before choosing, read the officer report and the committee minutes. If the condition was the reason the scheme was approved, a challenge that removes it invites the authority to revisit the permission.

Drafting to survive the test

For anyone writing conditions, or negotiating them in the fortnight before a committee, the practical rules are short.

State what has to be done, by whom, by when, and how compliance will be judged. Use plan numbers and revision letters. Avoid the passive where it hides the actor. Give a reason for each condition that names the policy and the harm it addresses, because a condition without a stated reason is hard to defend and easy to vary.

Avoid conditions that require future agreement with a party outside the permission. Avoid conditions duplicating other regimes, such as a condition requiring compliance with building regulations or with an environmental permit. Avoid pre-commencement conditions unless they are plainly needed, remembering that since the Neighbourhood Planning Act 2017 an authority cannot impose one without the applicant's written agreement.

And where a condition is negotiated down at the last minute, get the final wording in writing before the decision notice is issued. Arguing about what was agreed verbally at a committee is the least rewarding conversation in planning.

Illustrative example: a condition on a 12-dwelling permission requires the applicant to resurface a 60 m length of adjoining private lane and dedicate it as public highway before occupation. The lane is in third party ownership. The condition fails the second and third limbs, and it attempts to secure land dedication without compensation. The workable alternative is a negatively worded condition preventing occupation until an agreed access treatment within the applicant's land is complete, with a short Planning Statement explaining why the wider works cannot be delivered.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.