Certificate of Lawfulness vs Planning Permission

A Certificate of Lawfulness and planning permission both deal with the legality of development, but they are not the same thing. In the UK planning system, these are two distinct processes used for different purposes and at different stages of a project. Understanding the difference is essential for homeowners, developers and property professionals alike, especially when trying to confirm the status of existing works or preparing for new proposals.

A Certificate of Lawfulness is used to confirm that an existing or proposed development is lawful and does not require planning permission, either because of permitted development rights or because it has existed beyond the legal time limits for enforcement. Planning permission, on the other hand, is needed when you want to carry out development that is not automatically permitted and must be approved by the local planning authority before any work starts.

What Is a Certificate of Lawfulness?

A Certificate of Lawfulness is a formal legal document issued by a local planning authority under section 191 or 192 of the Town and Country Planning Act 1990. There are two main types. The first is a Certificate of Lawfulness for existing use or development, which confirms that a building, extension or change of use is lawful because it has been in place for a certain number of years without enforcement action. The second is a Certificate of Lawfulness for proposed use or development, which confirms that the planned works do not require planning permission because they fall within permitted development rights.

This certificate provides legal assurance that the development or use is immune from enforcement and can be safely relied upon by property owners, lenders and buyers. It is often used when selling a property or applying for refinancing, especially where alterations have been carried out without a record of planning permission.

What Is Planning Permission?

Planning permission is official consent from the local authority to carry out certain types of development that are not automatically permitted. This includes constructing a new building, extending a home beyond permitted development limits or changing the use of a building or land. A planning application must be submitted before the work begins and is assessed against national and local planning policies, design guidelines and material considerations such as neighbour impact, traffic and visual amenity.

Unlike a Certificate of Lawfulness, planning permission is not based on whether the work is legal but whether it is acceptable in planning terms. It involves public consultation, input from statutory consultees and assessment by planning officers or committees.

Key Differences Between the Two

A Certificate of Lawfulness does not require a planning judgement. The local authority is only concerned with whether the development is lawful according to the facts and evidence. It is not a subjective decision and does not consider whether the development is in line with planning policy or desirable in planning terms.

Planning permission, however, involves a full planning assessment. The decision takes into account the development plan, design quality, environmental impact and community feedback. Even if a proposal is well designed, it may still be refused if it conflicts with local policy.

Certificates are granted based on evidence. You must prove the development has been in continuous use or existence for the required period. For building works, this is usually four years. For changes of use, it is usually ten years. For proposed developments, you must show the work complies with permitted development rules.

Planning permission is based on plans and policy. The application is forward-looking and is considered on its planning merits. Supporting evidence may be needed, but the decision is made according to planning law and local development guidance.

Can You Use One Instead of the Other?

You cannot substitute one for the other. If you want to confirm that your proposed works are permitted and do not need planning permission, you apply for a Certificate of Lawfulness. If you want to build something that falls outside permitted development, you must apply for planning permission.

If you have already carried out work without permission and enough time has passed without enforcement action, you can apply for a Certificate of Lawfulness to regularise it. If the development is more recent or if the time limit has not yet expired, you will need to apply for retrospective planning permission instead.

When Should You Apply for Each?

You should apply for a Certificate of Lawfulness when you want legal confirmation that existing work has been in place long enough to be lawful, that a proposed extension or alteration falls within permitted development rights, or that you want peace of mind before proceeding with development.

You should apply for planning permission when you want to build a new home or large extension, change the use of land or buildings in a way not covered by permitted development, or make alterations in a conservation area or to a listed building.

Example in Practice

A homeowner in Kent built a single-storey rear extension in 2016 without planning permission. In 2023, they decided to sell the property. The buyer’s solicitor asked for confirmation that the extension was lawful. The owner applied for a Certificate of Lawfulness for existing development, submitting photographs, utility bills and a builder’s invoice to prove the work had been completed more than four years ago. The council granted the certificate, confirming that enforcement action could no longer be taken.

In contrast, another homeowner in the same area planned a side extension that exceeded permitted development limits. They applied for planning permission instead. The application was assessed against local design policies and approved with conditions related to materials and boundary treatment.

Conclusion

A Certificate of Lawfulness is not the same as planning permission. Each serves a different purpose within the UK planning system. The certificate confirms that something is legally allowed either because it has existed for long enough or because it qualifies as permitted development. Planning permission is required when the proposed work needs formal approval through the planning process. Understanding the difference can help you make the right application and ensure your development complies with the law.