Lawful Development Certificates and Prior Approval: What's the Difference?
PRIOR APPROVALPERMITTED DEVELOPMENT
Andrew Ransome
7/11/20266 min read
Two of the most commonly confused concepts in the English planning system are lawful development certificates (LDCs) and prior approval.
Both are routes that avoid a full planning application. Both involve an assessment by the LPA. And both are frequently encountered in the context of permitted development.
But they are fundamentally different in nature, and in the circumstances where each can and cannot be used.
Getting the distinction wrong can have serious consequences.
This article explains what each route is, how they interact in the context of permitted development and prior approval, and the critical situations where one route is available and the other is not.
What is a Lawful Development Certificate?
A lawful development certificate is a formal document issued by the LPA under section 191 or section 192 of the Town and Country Planning Act 1990 (TCPA90) confirming that:
Section 191 (existing use or development): the use of land or buildings described in the certificate is lawful at the date of the application; or that operations described have been carried out lawfully; or that a failure to comply with a planning condition or limitation has become lawful through the passage of time.
Section 192 (proposed use or development): the use or operations described in the application would be lawful if instituted or begun at the time of the application.
A lawful development certificate is not a grant of planning permission.
It is a formal legal determination of lawfulness — a certificate that the development does not require planning permission, or that planning permission has been properly implemented and the development is therefore lawful.
The lawfulness confirmed by A lawful development certificate under section 191(6) is conclusively presumed unless there has been a subsequent breach of planning control or other material change of circumstances.
This makes a lawful development certificate a valuable commercial document — particularly in property transactions, where a buyer or funder may require certainty that the existing use or development of a site is lawful.
What is Prior Approval?
Prior approval is the process by which a local planning authority considers specified aspects of a proposed permitted development before it can proceed under the GPDO 2015.
It is not planning permission, and it is not a certificate of lawfulness.
It is an approval by the LPA that certain specified matters — transport, flood risk, external appearance, natural light, and so on — have been assessed and are acceptable before the permitted development begins.
The prior approval system exists because Parliament, in granting planning permission by the GPDO, recognised that some categories of development — while acceptable in principle — require a degree of site-specific assessment before they can proceed. Prior approval provides that assessment without requiring a full planning application.
The Key Differences
The difference between a lawful development certificate and prior approval can be stated simply:
A lawful development certificate is a determination of whether development is or would be lawful — whether it needs planning permission, and if not, whether the PD right has been or could be properly implemented.
Prior approval is a determination of whether certain specified matters relating to an already-permitted development are acceptable — it does not determine lawfulness, and it does not grant permission.
This distinction has very real practical consequences, particularly in the prior approval context.
Where the Two Routes Interact: Prior Approval and Lawful Development Certificates
Can You Get a lawful development certificate Instead of Prior Approval?
No. Where a Class of permitted development requires prior approval as a pre-commencement condition, you cannot substitute a lawful development certificate application for the prior approval application.
The prior approval condition must be complied with — by obtaining prior approval (or a deemed grant of prior approval where the LPA fails to determine in time) — before development begins.
A lawful development certificate cannot be used to bypass this requirement.
Can You Get a lawful development certificate After Development Has Been Completed Without Prior Approval?
This is one of the most practically important questions in prior approval law, and the answer is clearly no — at least not under section 191.
There is no provision to grant prior approval retrospectively.
If development has already been completed without complying with the prior approval condition, a lawful development certificate under section 191 cannot be granted for that development.
The planning permission granted by Article 3(1) of the GPDO never came into effect, because the pre-commencement condition was never discharged.
Prior approval condition is a genuine pre-commencement requirement — not a formality that can be regularised after the event.
A lawful development certificate under section 192 (proposed development) also cannot be granted for proposed development where a prior approval condition has not been complied with by the date of the application.
This is because section 192(2) requires that the use or operations described would be lawful "if instituted or begun at the time of the application," and development that requires prior approval which has not been obtained is not lawful at that point.
When Can a lawful development certificate Be Granted in a Prior Approval Context?
A lawful development certificate can be granted — under section 191 or section 192 — for PD which does not require prior approval.
If a particular Class of permitted development carries no pre-commencement condition requiring prior approval (for example, certain minor agricultural works under Class B of Part 6 that fall below the prior notification threshold), a lawful development certificate is an appropriate route to confirm that the development is or would be lawful.
A lawful development certificate under section 191 can also confirm that prior approval was properly obtained and that the development as built accords with the approved details.
This is a useful route in property transactions where the original prior approval documentation may be incomplete or where there is a dispute about the extent of the approved development.
The Enforcement Immunity Route — and Its Limits
Under section 191 of the TCPA90, a lawful development certificate can be granted on the basis that development has become immune from enforcement action.
An owner of a building that was changed from commercial to residential use without prior approval might therefore seek an LDC under section 191 after the relevant limitation period has expired, arguing that the development has become lawful through the passage of time.
This argument can succeed — but it depends on establishing that the development was actually commenced and completed on the dates claimed, and that enforcement time limits have genuinely expired.
It does not retrospectively validate the prior approval process; it simply establishes that enforcement action is no longer available.
Lawful development certificates and the "Existing Use" Question
One of the most common uses of lawful development certificates in a permitted development context is to confirm the existing use of a building before a prior approval application is made.
This is particularly relevant for Class MA (commercial to residential) and Class Q (agricultural to residential) applications, where the existing use of the building on a specified date is a condition of the PD right.
Where there is any doubt about whether a building was in the qualifying use on the relevant date, a lawful development certificate under section 191 establishing the existing lawful use of the building can be a valuable step before making the prior approval application.
Lawful development certificates and Enforcement: The Ground (c) Appeal
In enforcement proceedings, where a notice alleges that the development constitutes a breach of planning control but the developer contends that the development is permitted development, the developer can appeal against the enforcement notice on ground (c) — that the matters alleged do not constitute a breach of planning control.
This is the enforcement equivalent of a lawful development certificate application.
The developer is asserting that the development is lawful, either because it is PD under the GPDO or because it has become immune from enforcement.
Where prior approval was required but not obtained, the ground (c) argument will fail — the development was not PD, because the pre-commencement condition was not satisfied.
Summary: When to Use Which Route
The correct route depends on whether you are seeking permission for proposed development, confirming an existing lawful position, or responding to enforcement action:
Use a prior approval application where the GPDO allows development to proceed but requires the local planning authority to approve specific matters before work begins.
Use a Lawful Development Certificate (LDC) under s191 or s192 where the aim is to confirm that an existing or proposed use or development is lawful.
Do not assume prior approval can be obtained retrospectively — if development requiring prior approval has already been carried out without obtaining it, neither a prior approval application nor an LDC will regularise the breach.
Where enforcement time limits have expired, an LDC under s191 may confirm that the existing use or development has become lawful, but this does not amount to the grant of planning permission or retrospective prior approval.
Where enforcement action is taken, the appropriate route may be an appeal, including a Ground (c) appeal where the argument is that planning permission was not required because the development benefited from permitted development rights.
Understanding the distinction between prior approval, lawful development certificates, and enforcement procedures is essential to selecting the correct planning route and avoiding unnecessary or ineffective applications.
Get Prior Approval and Permitted Development Planning Advice
If you are considering a project that may benefit from the prior approval route, get in touch for clear, practical advice on your options.
Andrew Ransome MRTPI - Email: andrew@andrewransome.co.uk
About me
Andrew Ransome is a Planning Director and a Chartered Member of the Royal Town Planning Institute (RTPI), with more than two decades of experience in town planning.
He specialises in delivering strategic planning solutions for complex developments across both rural and urban environments, helping clients navigate planning challenges and unlock development opportunities. Connect with Andrew on Linkedin.
Get in touch for planning advice: Email: andrew@andrewransome.co.uk
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