Article 3(5) and when permitted development is lost

Permitted development rights are not a property you own. They are a grant of planning permission made by article 3 of the General Permitted Development Order 2015, and that grant comes with switches that turn it off. The ones that catch investors most often are article 3(5), which removes the grant where the building or the use it relies on is itself unlawful, and article 3(6), which removes it where the work involves a new or widened access to a trunk or classified road. Knowing when permitted development does not apply is cheaper than discovering it during a sale.

How the Order makes rights conditional

Article 3(1) grants planning permission for the classes of development set out in Schedule 2. Everything after that narrows it.

The grant is subject to the exceptions, limitations and conditions written into each class, which is why the detail of Part 1 Class A matters so much on a householder extension. Beyond those class-specific limits, article 3 contains general disapplications that apply across Schedule 2 regardless of which class you are relying on.

That structure has a practical consequence. A proposal can satisfy every dimension and condition in its class and still not be permitted development, because a general provision in article 3 has removed the grant. Checking the class and stopping there is the mistake.

Conditions on an earlier permission removing rights

Article 3(4) is the provision most people have heard of. Nothing in the Order permits development contrary to a condition imposed on a planning permission granted otherwise than by the Order.

New housing estates are where it bites. Conditions removing Part 1 and Part 2 rights are routinely attached to estate permissions, so the house bought in 2019 with an obvious space for a rear extension may have no extension rights at all. The condition sits on the original estate permission, not on anything in the conveyancing file, and it is enforceable against every subsequent owner.

Wording matters, though. National guidance says conditions restricting permitted development should be used exceptionally and must be precise, and a condition that merely requires approval of details will not usually remove a class of rights. The detail of how that line is drawn is covered in development contrary to a condition and article 3(4).

Rights lost where the existing use is unlawful

Article 3(5) is the provision that surprises investors. The permission granted by Schedule 2 does not apply where, for a right granted in connection with an existing building, the building operations that constructed that building were unlawful, or where, for a right granted in connection with an existing use, that use is unlawful.

Read that against a typical conversion portfolio. A house converted to two flats without permission is an unlawful use, so none of the permitted development rights that attach to a dwellinghouse operate on it. A garage built without permission and in breach of the Part 1 limits is an unlawful building, so you cannot rely on Part 1 to extend it or on Part 2 to alter it.

The effect compounds. An unlawful rear extension means the "original dwellinghouse" calculation for a further extension starts from a building that was never lawfully enlarged, and the authority will treat the whole as requiring permission.

Immunity changes the picture, and only up to a point. Once a breach becomes immune from enforcement it cannot be enforced against, and whether the use or building thereby becomes lawful for article 3(5) purposes depends on the facts and on obtaining a certificate. The Levelling-up and Regeneration Act 2023 moved the enforcement time limits in England towards a single ten year period, so check when that change took effect against your breach date before assuming the old four year rule applies. The practical detail sits in enforcement time limits for permitted development breaches.

Access to a trunk or classified road

Article 3(6) disapplies the Schedule 2 grant where the development requires or involves the formation, laying out or material widening of a means of access to an existing highway that is a trunk road or a classified road. It also catches development that creates an obstruction to the view of highway users so as to be likely to cause danger.

This is a live issue for small commercial and residential conversions on main roads. A change of use that needs a new vehicular crossover onto a B road falls outside permitted development for that reason alone, whatever the class says about the use itself.

Classification is a question of fact you can check with the highway authority. A road's name tells you nothing, and plenty of unclassified roads look more major than classified ones.

Development requiring other consents first

Two further general restrictions work differently and both are easy to miss.

Where a proposal would be development requiring environmental impact assessment, the Order does not grant permission for it unless the relevant screening route has been followed. That matters for prior approval applications under Parts 3 and 20, and the interaction is set out in prior approval applications and EIA screening.

Where a proposal is likely to have an effect on a European site, the Habitats Regulations restrict reliance on the Order until the appropriate assessment has been carried out. In nutrient-sensitive catchments this has become a real constraint on conversions that add bedrooms.

Separately, permitted development is a planning answer only. Listed building consent, conservation area consent for demolition, protected tree consents, Building Regulations approval and a licence for a house in multiple occupation all remain required, and none of them is affected by the grant in Schedule 2.

Checking the planning history properly

Most article 3(5) problems are discoverable before purchase if somebody actually looks.

1. Obtain the full planning history for the address from the authority's register, not just the most recent decision, and read the conditions on every permission that relates to the building.
2. Look for the estate or outline permission where the property is on a post-1990 development, because the restrictive condition usually sits there.
3. Compare the building on the ground with the approved drawings, element by element, for extensions, outbuildings, roof alterations and hardstanding.
4. Ask the vendor directly whether any works were carried out without permission, and whether any enforcement enquiry has ever been made.
5. Check for an Article 4 direction covering the address, which the authority publishes and which is also recorded in the national planning data.
6. Confirm the road classification with the highway authority where any access work is contemplated.

A conveyancing search will reveal some of this and not all of it. The gap is usually the comparison between the approved drawings and the building as built, which nobody does unless they are asked to.

Confirming the position formally

Where the answer matters, a professional opinion is not the same as a determination. The only formal way to establish that works or a use are lawful is a Lawful Development Certificate: section 191 of the Town and Country Planning Act 1990 for something that already exists, and section 192 for something proposed.

A certificate under section 192 is the route to take before spending money on a scheme that depends on permitted development. It is determined on the legal position rather than on planning merits, the authority cannot refuse it because it dislikes the proposal, and a positive certificate binds the authority.

The application needs evidence rather than argument: drawings, measurements from the original dwellinghouse, and in a section 191 case, statutory declarations and dated photographs establishing the period of the breach. Set the legal reasoning out properly, as you would in a Planning Statement, and expect the authority to test it.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it, and remember that only a Lawful Development Certificate formally confirms that works are lawful.

Enter your postcode on PlanScope to see which documents a conversion or extension is likely to need.

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