Permitted development alongside a live planning permission

Holding a planning permission does not cancel your permitted development rights, and using permitted development does not invalidate the permission. Both can sit on the same land at once. The question that matters with permitted development with existing permission is narrower: whether a condition on the permission has removed the rights, and whether carrying out one scheme makes the other physically impossible.

Get that wrong and you build something unlawful on a site where you believed you had two options.

Holding more than one consent on a site

English planning law lets a landowner hold several extant permissions over the same land and choose which to implement. There is no rule requiring you to pick one at the point of grant, and applying for a second scheme does not withdraw the first.

The limit comes from the Pilkington principle, taken from a 1973 case where an owner had two permissions for a bungalow on the same holding. Once the first was built, the second could no longer be implemented, because carrying it out would have been physically impossible on the land as it then stood.

So the test is practical. Look at the site as it will exist after you have built scheme A, then ask whether scheme B could still be carried out in accordance with its approved plans. If the answer is no, scheme B is dead even though the permission has not expired.

Whether implementing a permission affects your rights

Permitted development rights attach to the building or the land, not to the permission. A house extended under a full planning permission keeps its rights under Schedule 2, Part 1 of the General Permitted Development Order unless something removes them.

Three things remove them in practice. A condition on the permission that withdraws specified classes. An Article 4 direction made by the authority over the area. Or the site's status as article 2(3) land, which restricts rather than removes.

There is also a timing point people miss on new build. Class A permits an enlargement of a dwellinghouse, so the dwellinghouse has to exist first. You cannot extend a house under permitted development while it is still a set of foundations authorised by an outline permission.

Conditions that tie the two together

Read the conditions before assuming anything. Two types matter.

The first withdraws permitted development, and the courts require clear words to do it. A condition saying that no development within Classes A to E of Part 1 shall be carried out without express planning permission is effective. Vaguer wording about "no further development" has been read down where it was not clear enough to remove a statutory right.

The second requires the development to be carried out in accordance with the approved plans. Councils sometimes argue that a later outbuilding or extension breaches that condition because the site no longer matches the drawings. The better view is that permitted development carried out separately is its own development, though the argument is common enough that a certificate is worth obtaining where value turns on it.

Our note on Class AA upward extensions and their prior approval limits shows how tightly drawn some of these rights are before any condition is applied.

Physical impossibility and part implementation

A permission is implemented by carrying out a material operation, which can be as little as digging foundation trenches or laying out a new access, provided the work is genuine and in accordance with the permission.

Once implemented, the permission does not expire. That matters where a site holds a valuable older consent: a material operation before the expiry date keeps it alive, and the fallback position it creates can support a later application for something else.

Part implementation is where disputes start. Building the garage from scheme A and the house from scheme B produces a development that matches neither set of approved plans, and the authority can treat the whole as unauthorised. Where you want elements of two schemes, the clean routes are a section 73 application to vary conditions or a fresh application for the hybrid you actually want.

Recording which scheme was built

Keep a build record. Nobody asks for it during construction. Someone will ask five years later, during a sale, when the person who did the work has moved on.

What is worth holding:

• the decision notice and approved plans for the scheme you implemented, marked as such
• dated photographs of the material operation that implemented it
• building control records tied to the same drawings
• a certificate of lawfulness for any permitted development works carried out separately
• correspondence confirming discharge of every condition

Where permitted development has been used alongside a permission, a certificate of lawfulness under section 192 for proposed works, or section 191 for works already done, converts an arguable position into a documented one.

Store it somewhere that survives a change of agent or contractor. A shared folder handed over at practical completion is worth more than a box of paper in a site office.

Risks at sale or refinancing

Conveyancing solicitors check that what stands on site matches a permission and that conditions were discharged. A garden building put up under Class E next to a house extended under a full permission looks fine to you and raises a question for them.

The answers that satisfy a buyer's solicitor are a certificate of lawfulness, or an indemnity policy where a certificate is not available. Indemnity policies cost less and arrive faster, though they insure against enforcement rather than confirming lawfulness, and an application to the council after the policy is taken out usually voids it.

Lenders take a similar view on new build sites where multiple permissions exist. If the title plan and the approved plans do not obviously correspond, expect a requisition.

Getting the position confirmed

Where the value at stake justifies it, apply for a certificate rather than relying on advice.

An application under section 192 asks the authority to confirm that proposed works would be lawful, and it is decided on the facts and the law rather than on planning merits. The authority cannot refuse because it dislikes the scheme. You need to describe the works precisely, supply plans, and address any condition that might have removed the right.

Allow eight weeks for determination, and expect the authority to ask for more detail on dimensions than a planning application would need, because a certificate has to describe precisely what is lawful.

Where the works are already done, section 191 covers them, and the burden of proof sits with you. Photographs, invoices, delivery notes and statutory declarations all help.

One honest caveat. Officers differ on how they read conditions withdrawing rights, and a certificate refused on that basis goes to appeal rather than to negotiation. Building the point into a planning statement at application stage, and asking for the condition to be omitted or narrowed before it is imposed, costs nothing and avoids the argument entirely.

Enter your postcode on PlanScope to see the supporting documents a householder or small site application is likely to need, and read our note on when a garden office stops being incidental before relying on Class E.

This is general guidance, not legal advice, and a Lawful Development Certificate is the only formal way to confirm that works are lawful. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.