A lawful development certificate for proposed work costs £969 at the starting point in London: from £545 drawings + £150 survey (£695 total) to us and £274 to the council. A certificate for work already built has a different fee, which the next section sets out, because the council charges the full amount.
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The certificate answers one question: is this lawful as it stands, or as you plan to build it? It does not ask whether the council likes the design. That is why it is the paper a buyer, a lender or a neighbour's solicitor asks for when work relies on permitted development rather than an approved application.
What does the council charge, and does it depend on the type?
Yes, it depends on whether the work is built yet. The government's fee guidance sets out two cases (MHCLG, Fees for planning applications):
| Certificate | Council fee |
|---|---|
| Proposed development (section 192) | Half the planning application fee: £274 for a house extension, on the 1 April 2026 table |
| Existing use or completed development (section 191) | The same as a new permission for that use or operation: £548 for a householder case |
The 1 April 2026 figures come from the MHCLG fee table. The fee for other types of work, such as a change of use, is on the same list and is different.
What do you pay us for?
For the evidence. The certificate is not a favour from the officer; it is a decision on facts, and the facts are your drawings. The guidance says the applicant's evidence must be "sufficiently precise and unambiguous" to justify a certificate on the balance of probability (MHCLG, Lawful development certificates).
Our fee runs in three stages, written on the price list: survey at £150, existing and proposed drawings at £450 and submission at £95. The drawings do more than a planning application's because they must show, dimension by dimension, that each permitted development limit is met: depth, height, eaves, distance from the boundary, materials.
When is a certificate worth the money?
Three cases come up most often in London:
- You are relying on permitted development and want it in writing. A loft with a rear dormer, a single-storey rear extension or an outbuilding in the garden can all be lawful without an application. The certificate turns "we think so" into a document. Our permitted development checker shows whether you are in that group first.
- You are selling or remortgaging. A solicitor wants to see that unapproved-looking work is lawful. For old work that may be immune from enforcement, the certificate records that.
- You want certainty before the builder starts. Once a proposed-work certificate is granted, the guidance says the development is presumed lawful unless a material change happens before it begins (MHCLG, Lawful development certificates).
Where an application is needed instead, or the project is a larger home extension, a different route applies; see our prior approval cost post. For work that needed permission and never had it, the route may be retrospective planning.
How old does work have to be to be immune?
In England, ten years for most unauthorised building work, counted from when it was substantially completed (section 171B). That is a legal limit on enforcement, not a drawing, and a certificate is how you prove it with evidence of dates: invoices, dated photographs, utility bills, building control records. Our certificate of lawfulness guide explains the transitional rules that still catch some older work.
If the council has no evidence against yours and your evidence is precise, the guidance says there is no good reason to refuse (MHCLG). That is a statement about the test, not a promise about your case.
How common are these in London?
Often. London's councils recorded 12,141 lawful development certificates in the PS1 return for July 2025 to June 2026 (MHCLG live table PS1). The number per borough varies a lot with housing type and how much permitted development a borough has.
Frequently asked questions
Is a certificate the same as planning permission? No. It records that something is lawful without needing permission, or is immune from enforcement. If your project goes beyond permitted development, you need an application, not a certificate.
Can I use the certificate for a different design later? No. It covers what it describes. A change to the depth, height or position of the work is a different development and needs its own check.
Do I need one for permitted development? Not by law. You may build under permitted development without any paper. The certificate is optional, and most owners buy it for the sale or for peace of mind.
What if the council refuses the certificate? The fee is not refunded, but the refusal states the reasons, and a revised application with better evidence or a corrected design is possible. We give you our view of the evidence before you apply.
If the application goes through the Planning Portal, the Portal adds its own service charge: nothing, £99 or £149 including VAT, depending on the application type and complexity, paid to the Portal at submission and not normally refunded with a council fee (Ashford Borough Council, Planning Portal service charges, 11 September 2026). It is not ours and not the council's. Other submission routes exist; where your council accepts one without a charge, we can use it.
