Certificate of Lawful Development (LDC)

If you're looking at building an annex, you'll almost certainly already know about Certificates of lawful Development, or LDCs. Below will give you an overview of what's covered and how to apply.

If you need help with this:

Please ask and we can put you in touch with a independent specialist garden annexe planning consultant.

What an LDC is 

A Certificate of Lawful Development (also called a Lawful Development Certificate, LDC) is an official document from the council confirming that a proposed or existing development is lawful.

For a granny annexe, you might seek an LDC to confirm that your plan doesn’t require planning permission (for example, if you believe it’s permitted development or falls under the Caravan Act rules).

Obtaining this certificate means the local authority agrees your annexe is lawful and cannot take enforcement action against it as described.

Essentially, it de-risks a PD or caravan-based project by giving you written legal confirmation up front.

When a Certificate of Lawful Development Applies (Proposed vs Existing)

There are two types of LDC certificates:

1. One for proposed development and
   
   
2. One for existing development.

Most annexe projects will use a proposed LDC (under §192 of the Town and Country Planning Act 1990) before construction. You’d use this if you think your annexe can be built without planning permission (e.g. under PD rights or as an ancillary mobile home) but want certainty.

An existing LDC (under §191) is used if, for example, an annexe has already been built or a caravan installed and you need to prove it’s been lawful for long enough (or was lawful when done).

Proposed LDCs are more common to avoid future disputes – essentially asking the council “Is this lawful?” before going ahead.

If you need help with this:

Please ask and we can put you in touch with a independent specialist garden annexe planning consultant.

How to Apply for an LDC

You apply to your Local Planning Authority (LPA) much like a planning application, but specifically for a Lawful Development Certificate. This involves a form (available via the Planning Portal), a site plan, drawings of what you propose, and a fee (an LDC for a proposed development typically costs half the equivalent planning application fee).

Evidence is crucial

Since you are asserting the development is lawful, the burden is on you to provide proof or strong justification for that claim.

For a proposed annexe, this means including clear plans/specifications and a written explanation tying it to PD rules or the caravan definition (with evidence like the unit’s dimensions if claiming it’s a caravan).

The council will assess the facts against legal definitions – no subjective “planning merits” are involved, just law. If the council is satisfied, they issue the certificate, which is a legally binding confirmation.

If you need help with this:

Please ask and we can put you in touch with a independent specialist garden annexe planning consultant.

Legal Effect of an LDC

An LDC, once granted, is powerful.

It confirms your annexe is lawful as of the date issued and gives you a defence against enforcement action.

For example:

• If you have an LDC stating your proposed garden building is permitted development, the council cannot later insist you needed planning permission (as long as you build exactly per the LDC).
  
  
• It “freezes” the lawfulness on the date of application – meaning even if rules change later, your certificate remains valid for what was described. Keep in mind, an LDC is not mandatory – you can proceed without one if confident in your rights – but it is often wise for contentious cases (like an annexe that might be borderline PD or an ancillary mobile home).

Many people obtain an LDC for peace of mind or to help in selling the property later (buyers and solicitors like to see proof that the annexe is legal).

What if your LDC application is refused?

If an LDC is refused, you can appeal that decision, or instead move to a planning application.

Note that a refusal doesn’t necessarily make the project unlawful; it may mean the council wasn’t convinced by the evidence or interprets the rules differently. In such cases, seeking full planning permission might be the more straightforward route.


Important: You are responsible for making sure that you follow all rules pertaining to your own property and the area you are in and that you obtain the relevant permissions. 

If you need help with this:

Please ask and we can put you in touch with a independent specialist garden annexe planning consultant.