For developers, landlords and owners who need the council's written answer
Lawful Development Certificate: How to Prove a Use or a Conversion Is Lawful
Sviatoslav JerdetchiiCEO & Founder of Craftex. Updated , 10 min read
The short answer
A lawful development certificate is the council's formal decision that a use, a building or a proposed change is lawful for planning purposes, so no planning permission is needed and no enforcement can follow. It grants nothing new: it records what the law already allows.
- Existing use (section 191): proves a use or building has been there long enough, or never needed permission. Council fee: the same as a full application.
- Proposed use (section 192): confirms a conversion or extension is permitted development before you buy, borrow or build. Fee: half the full application fee.
- In England the enforcement time limit is ten years for every breach begun since 25 April 2024; work finished or a use begun before that date keeps the old four-year or ten-year limit.
- Decision in eight weeks. Refused or ignored, you can appeal. Lenders and buyers ask for the certificate because the lawfulness it records is conclusively presumed.
A lawful development certificate is the council's written confirmation that something is lawful for planning purposes. It covers a use or building that already exists, or a change you propose to make. Nothing is granted. The certificate records what planning law already allows, and once issued that lawfulness is conclusively presumed.
That is why it matters to the people we work with. A buyer's solicitor asks for one. A lender's valuer wants it in the pack. A developer converting offices to flats under permitted development and prior approval needs the use history settled before the deposit goes down.
This guide is written for them, by the team that checks the history and then builds the conversion. Have a building in mind? Check if it qualifies and we will read the planning record with you. Homeowners use the same certificate for extensions and lofts; the rules below cover that too.
What a lawful development certificate is and what it proves
The certificate comes from the Town and Country Planning Act 1990. Two sections create two different documents. The first job is to know which one you are asking for.
Section 191 covers existing use or development. You ask the council to confirm that a use, works already carried out, or a breach of a condition is lawful now.
Lawful has a precise meaning. No enforcement action can be taken: the time for it has run out, or no permission was ever needed. The use must also not breach an enforcement notice in force.
Section 192 covers proposed use or development. You describe what you intend to do. The council confirms it would be lawful if you began it on the day you applied. In practice that means permitted development, or a change within one use class, so no planning application is needed.
The certificate is only as good as its wording. Government guidance tells councils to insist on a precise description of the use or works, not just a use class. Sui generis and mixed uses need particular care. Ask for a wide description you cannot prove, and the council can certify a narrower one.
Existing use or proposed use: which certificate you need
The question to ask is simple. Are you proving the past, or clearing the future?
An existing-use certificate is the backward-looking one. It fits a landlord whose building has been flats above a shop for decades, with nothing on the register. It fits an owner whose roof addition went up without consent and has passed the time limit. It fits a yard or workshop use that grew up over the years and now needs refinancing.
A proposed-use certificate is the forward-looking one. It fits a developer who wants written confirmation that a building sits in Class E, so Class MA is open to it. It fits an owner planning permitted development works who wants the council to say so before the lender asks. It fits any change within a use class a buyer wants documented.
| Existing use or development (s.191) | Proposed use or development (s.192) | |
|---|---|---|
| What it proves | A use, works or breach of condition is lawful now | A proposed use or works would be lawful if begun today |
| Typical reason | Sale, refinance, immunity from enforcement | Permitted development, Class MA eligibility, a change within a use class |
| Council fee | Same as a full planning application for that development | Half the full application fee |
| Decision | Eight weeks | Eight weeks |
| How long it holds | Permanent for what it describes | Until a material change in the relevant facts before you start |
One application can do both jobs where the facts allow it. A combined application under section 191 for an existing use and a breach of condition pays both fees added together.
The ten-year rule since April 2024
Most existing-use certificates turn on time. If the council can no longer take enforcement action, the use or building is lawful, and the certificate records that.
Since 25 April 2024 England has had one time limit, set by the Levelling-up and Regeneration Act 2023. Building and other operations become immune ten years after they were substantially completed. A change of use of a building to a single dwelling becomes immune ten years after the breach. Every other breach has always had ten years.
The old four-year rule is not dead for everyone. Work substantially completed before 25 April 2024 is still judged under the four-year limit. So is a change of use to a single dwelling that began before that date. Wales keeps four years for both.
The first thing we establish is therefore the date: when was the work finished, or when did the use begin?
Two things never become lawful by waiting. Relevant demolition of a building has no time limit. And where a breach was deliberately concealed, a magistrates' court can make a planning enforcement order. That lets the council act for a year after the limit has passed.
If either is in play, say so at the start, not after the fee is paid. Where the time has not run, the route is retrospective planning permission, not a certificate.
Hired Craftex for our conversion project. We had to convert a 600m2 office into 8 apartments. Guys did an excellent job in terms of program efficiency and quality of the finishes which gave us a big upside to exit the project 2 months faster than other competitors’ timelines.
The evidence a council needs
The burden of proof is on you, and the test is the balance of probability. Government guidance says a refusal is hard to justify where your evidence is sufficiently precise and unambiguous and the council has nothing to contradict it. The council may gather its own evidence. It must then show it to you and let you respond.
Proving an existing use
The file has to show the use began and then carried on without a break for the whole period. Councils do not publish a fixed list. We build it from what a planning inspector expects to see.
- Dated photographs of the building and its use, inside and out, over the years.
- Leases, tenancy agreements and rent records showing who occupied what and from when.
- Council tax or business rates records, which the council itself can check.
- Utility bills, invoices and insurance schedules addressed to the premises in its current use.
- Electoral roll entries, post and delivery records for residential uses.
- Statutory declarations from owners, tenants, neighbours and tradespeople who know the history, sworn before a solicitor.
Proving a proposed use
The evidence is different. The council wants a clear description of what you propose and drawings where works are involved. It also wants proof of the current lawful use your proposal relies on. For a Class MA conversion that means a continuous two years in Class E before the application.
Making a false or misleading statement to get a certificate is a criminal offence. The council can also revoke a certificate obtained that way, after notice and fourteen days for representations. No compensation is payable. That is a good reason to let someone experienced assemble the file.
Fees, the eight-week decision and the appeal
The council fee depends on what you ask for. For an existing use or operation it is the same as a full planning application for that development. For a proposed use or operation it is half. A certificate that it is lawful not to comply with a condition carries a flat fee.
| Application | Fee |
|---|---|
| Existing use or operation | Same as the full application fee for that development |
| Existing use: lawful not to comply with a condition | £309 (£360) |
| Proposed use or operation | Half the full application fee |
| Full fee reference: change of use to fewer than ten dwellings | £610 per dwelling (£700) |
| Full fee reference: other change of use of a building or land | £610 (£732) |
| Class MA prior approval, Class E to homes | £260 per dwelling (£323) |
The December figures depend on Parliament approving the draft fee regulations. Professional fees for the drawings, the evidence file and the statutory declarations sit on top of the council fee.
Eight weeks, then the right to appeal
The council must decide within eight weeks beginning the day after it receives a valid application. A longer period is possible only if you agree it in writing. A refusal must state the full reasons and tell you that you can appeal to the Secretary of State.
You can also appeal if the council certifies a narrower description than you asked for, or gives no decision within the eight weeks.
A refusal is not a finding that the use is unlawful. It means the evidence did not satisfy the council on that day. Many owners strengthen the file and apply again rather than wait for an inspector.
Class MA: prior approval or a lawful development certificate
This is where most of our enquiries come from, so it gets its own section. Class MA lets a building in Class E change to homes without a planning application. Class E covers offices, shops, restaurants, clinics, gyms and light industry.
Class MA is not automatic. You apply to the council for prior approval, and it has 56 days to decide. It looks at transport, contamination, flooding, noise, natural light, fire safety and a few other matters.
The building must have been in Class E use for a continuous two years before the application. It cannot be listed. It cannot sit in a National Park, an area of outstanding natural beauty or a World Heritage Site. The former three-month vacancy test and the floorspace cap were removed in March 2024.
So where does the certificate fit? A prior approval decides the matters above. It does not decide whether the building was lawfully in Class E for two years. If that history is clean on the register, go straight to prior approval. If it is not, a proposed-use certificate is the cheaper question to settle first.
- Clear history on the register: apply for Class MA prior approval directly.
- Use never formally permitted, or a mix of uses: a section 191 certificate for the existing use, then prior approval.
- Article 4 direction removing Class MA: neither route works; a planning application is needed.
- Listed building: Class MA is excluded; the conversion needs planning permission and listed building consent.
We obtain a certificate before Class MA whenever the two-year Class E history is in doubt. The right itself is explained in our guide to commercial to residential permitted development. The choice of application route is in outline or full planning permission, or a certificate of lawfulness.
Why lenders and buyers ask for it
A planning permission can be challenged, lapse or carry conditions nobody read. A section 191 certificate cannot be undone by a change in policy. The lawfulness it records is conclusively presumed for what it describes. That is the document a purchaser's solicitor wants when the use on the ground does not match the planning register.
For a lender, the certificate removes a risk from the valuation. A building let as flats with no permission for flats has income an enforcement notice could stop. A certificate turns that into an ordinary investment. A proposed-use certificate does the same before a conversion loan: the council has said in writing that the scheme needs no planning permission.
For a developer buying a building to convert, that changes the price conversation. We put the use history check at the front of every commercial to residential conversion appraisal.
One client wrote this after a shop-to-flat conversion in Chelsea. "Quote was clear, no hidden extras, and they actually stuck to it, which is rare."
That only happens when the planning question is settled before the price is fixed.
How we use the certificate before a conversion
The certificate is a tool, not the goal. The goal is a building that is converted, let or sold on the date you planned. This is how it sits in our process.
First, we read the planning history: the register, past decisions, conditions, any Article 4 direction and the use class record. Then we assemble the evidence for the certificate. Or we confirm it is not needed and go straight to prior approval or a planning application through our planning consultancy.
Our Development Director has taken more than 10,000 homes through planning. That experience decides which route is fastest.
Then the same team prices the conversion. Construction is an in-house department, with about 60% of the labour directly employed. So the cost plan comes from the people who will build it.
You get a route, a council fee, a programme and a construction price together, before you commit to the building. Looking at a building now? Check if it qualifies and send us the address.
Before you apply for a lawful development certificate
- Decide which certificate: existing use (section 191) or proposed use (section 192).
- Pin down the date the works were finished or the use began, and which time limit applies.
- Check the planning register for conditions, enforcement notices and Article 4 directions.
- Describe the use precisely, floor by floor, not by use class alone.
- Gather dated evidence for every year of the period and statutory declarations for the gaps.
- Budget the council fee, and the drawings and declarations on top.
- Diary the eight weeks and the appeal route if the council is silent.
- Price the conversion before you exchange, so the certificate and the budget arrive together.
