Lawful development certificate: existing or proposed use

Two certificates, two sections, two very different problems. A certificate under section 191 of the Town and Country Planning Act 1990 confirms that something already happening is lawful. A certificate under section 192 confirms that something you intend to do would be lawful if you did it. The lawful development certificate existing vs proposed distinction decides what evidence you need, what it costs and what happens if you are refused.

For a landlord who has been letting a house in multiple occupation for years without permission, it is section 191. For one about to convert a shop to a flat under permitted development and wanting certainty before committing, it is section 192.

What each section certifies

Section 191 covers three things: that an existing use is lawful, that operations already carried out are lawful, and that a use or operation in breach of a condition is now lawful because the time for enforcement has passed. The certificate describes what exists and confirms its lawfulness as at the date of the application.

Section 192 covers proposed use or operations. It asks whether, on the facts as described, the thing you propose would be lawful. It does not grant permission and it does not confer any right beyond the description in the certificate.

Both produce a document that binds the council. A certificate, once issued, is conclusive as to the lawfulness of what it describes, unless the description was materially inaccurate or material information was withheld.

Burden of proof

The onus sits on the applicant in both cases, and the standard is the balance of probabilities. The council is not required to disprove anything.

An important principle applies to existing use applications: the applicant's own evidence does not have to be corroborated by independent evidence to be accepted. If the account given is precise and unambiguous and the council has nothing to contradict it, the council should grant. In practice, uncorroborated evidence from an interested party rarely reads as precise and unambiguous on its own, so corroboration is what wins.

Councils also cannot refuse on planning merits. Whether the HMO is a nuisance, whether parking is inadequate, whether neighbours object, none of it is relevant. These are legal determinations, and a refusal must identify a legal or evidential failing.

Evidence that persuades on an existing use

The immunity period is the thing you are proving. The Levelling-up and Regeneration Act 2023 moved the immunity period for breaches of planning control in England to ten years, replacing the earlier four year rules for operational development and change of use to a single dwellinghouse. Which regime applies depends on when the breach occurred, so establish the breach date first and check the position before assembling anything.

What you need is continuity across the whole period, with no gaps:

• statutory declarations or sworn statements from people with direct knowledge, covering defined date ranges
• tenancy agreements and rent records, which for an HMO case are the strongest single source
• council tax records and any HMO licensing history, which the council holds itself
• utility bills and supply records showing separate services
• electoral roll entries
• dated photographs, invoices for works, and delivery or trade records

Gaps are the usual cause of refusal. A vacancy of a few months may not matter. A year with nothing at all, or a period where the property reverted to single family occupation, breaks continuity and resets the clock.

Deliberate concealment is worth a warning. Where a breach has been actively concealed, the council can seek a planning enforcement order and the immunity argument may fail entirely. Concealment is not the same as simply not drawing attention to something, but the line is closer than people assume.

Evidence on a proposed use

A section 192 application is an argument about law applied to a drawing. What you submit is the description of the proposal, accurate drawings, and a statement setting out why the proposal is not development at all, or is permitted development under a named class, with each limb of that class addressed.

Precision in the description is everything. A certificate confirms what it describes, so a vague description produces a certificate of limited use, and an inaccurate one produces a certificate that can be revoked. Spell out the dimensions, the materials and the extent of the works.

Where the proposal relies on a permitted development class, walk through the conditions and limitations one by one. An officer reading a statement that addresses Class A.1(a) through to A.3 in turn will find it much easier to grant than one reading a general assertion.

Fees and cost

The fee for a section 191 certificate is the same as the fee for a planning application for the equivalent development. The fee for a section 192 certificate is half that. The difference is significant on a larger scheme and negligible on a householder proposal.

Fees are indexed and change on 1 April, so check the current schedule on the Planning Portal before budgeting. The real cost in a section 191 case is rarely the fee. It is assembling and verifying a decade of evidence, and where declarations are being taken it is worth paying for them to be properly drawn.

If a certificate is refused

An appeal lies to the Secretary of State under section 195, dealt with by the Planning Inspectorate. It is a merits appeal on the legal question, usually by written representations, and it is a genuine second chance rather than a review of the council's reasoning.

The alternative is often better. A refusal on a section 191 application usually identifies the gap in the evidence, and reapplying with that gap filled is faster and less costly than an appeal. A refusal on a section 192 application tells you the proposal is not permitted development, at which point a planning application with a proper Planning Statement is the sensible response.

Be aware of one risk. Applying for a certificate for an existing unlawful use puts the council on notice of that use. If the evidence falls short of the immunity period, you have handed the enforcement team a file. Take advice before applying where the dates are marginal.

Using a certificate at sale or refinancing

This is why most certificates get applied for. A buyer's solicitor raising an enquiry about an unauthorised conversion wants either a certificate or indemnity insurance, and certificates are the better answer because insurance does not make the use lawful.

Certificates appear on the local land charges register and come back on a search, which is exactly what you want. Get the certificate before marketing rather than during a transaction, because the determination period runs to eight weeks and a buyer under time pressure will discount for the uncertainty.

Why both types fail

The recurring reasons are short and avoidable:

1. Gaps in the evidence across the immunity period.
2. A description that does not match what actually exists or what is actually proposed.
3. Confusion about the planning unit, particularly where a building has been subdivided.
4. Reliance on a permitted development class where one limitation has been overlooked.
5. Applying under the wrong section, usually section 192 for something already built.
6. Assuming the council will investigate on your behalf. It will not.

Browse the 66 PlanScope report types to see which supporting documents your application needs, and see pricing for what a draft costs.

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