Agricultural prior notification or Class Q: the ten year bar

If you are weighing agricultural prior notification against Class Q on the same holding, the thing to understand first is that they interfere with each other. Class Q is not available where development under the agricultural building rights in Part 6 has been carried out on the established agricultural unit within the ten years ending with the date the Class Q development begins. So putting up a new shed under prior notification can close off a barn conversion for a decade, and the restriction works in both directions.

That is a sequencing decision, and it needs making before anything is built rather than after.

What each right actually does

They are different rights doing different jobs, and the only thing they share is that both run through a short determination process rather than a full planning application.

The ground area limit under Part 6 Class A was changed by amendment in 2024 and now differs according to whether the building is for livestock, so check the current text of Class A for the figure that applies to your proposal rather than relying on a remembered number.

Part 6 in outline

Class A of Part 6 permits works for the erection, extension or alteration of a building, and excavations or engineering operations, which are reasonably necessary for the purposes of agriculture within an agricultural unit of five hectares or more. Prior notification applies to the erection of a building, to extensions and alterations above a defined threshold, to the formation or alteration of a private way, and to excavations and deposits above a stated area.

The council's role is narrow. It decides whether its prior approval is required to the siting, design and external appearance of the building, and nothing else. It cannot refuse the building, cannot ask whether the farm needs it as a matter of policy, and cannot impose conditions about how the land is used.

Height, proximity to classified roads and the 400 metre separation from protected buildings for livestock and slurry structures are absolute limits. Exceed any of them and the right is lost.

Class Q in outline

Class Q permits the change of use of a building and land within its curtilage from agricultural use to use as dwellings, together with the building operations reasonably necessary for that conversion.

The eligibility conditions do most of the work:

• the building must have been in agricultural use as part of an established agricultural unit on the reference date set out in the Order, currently 24 July 2023, or when it was last in agricultural use before that date
• where the building was not part of an established unit on that date, the unit must have been established for at least ten years before the development begins
• the limits are up to ten dwellings per agricultural unit, 1,000 square metres of total floorspace, and no individual dwelling exceeding 150 square metres
• the building must not be listed, a scheduled monument, or on article 2(3) land, which covers conservation areas, National Parks, the Broads, National Landscapes and World Heritage Sites
• sites of special scientific interest, safety hazard areas and military explosives storage areas are excluded
• the building must be capable of conversion without substantial rebuilding, because the right permits conversion rather than the construction of a new dwelling behind a retained wall

The amended right also allows a single storey rear extension of limited depth on existing hardstanding, which was not available before 2024 and which solves the common problem of a barn with no practical entrance arrangement.

Prior approval is then sought on six matters, and each of them is a place where an application fails. Highways and access usually means a visibility splay and a passing place, and a short Transport Statement is often the quickest way to deal with it. Noise means agricultural operations, a grain drier or a poultry unit next door, and that is a Noise Impact Assessment question. Contamination means sheep dip, fuel tanks, asbestos sheeting and pesticide stores, and a contaminated land assessment prepared by a suitably qualified and experienced person in accordance with BS 10175 is legally expected for that work. Flooding means the site's flood zone, and where the barn sits in Flood Zone 2 or 3 a Flood Risk Assessment is required.

The fifth matter, whether the location makes residential use impractical or undesirable, is the one with the least guidance and the widest discretion. Remote buildings with a long unmade access, no services and no realistic emergency vehicle access are where authorities exercise it.

How a Part 6 building affects a later Class Q claim

This is the interaction that catches most farms out, and it is worth stating precisely.

Class Q is not available where development under the agricultural building rights in Part 6 has been carried out on the established agricultural unit within the ten years ending with the date on which the Class Q development begins. The bar attaches to development actually carried out, not to the date of a prior approval letter, so a notification obtained and never acted on does not trigger it.

Three consequences follow.

The test applies to the agricultural unit, so splitting the land into separate titles or transferring a field to a family member does not avoid it. The unit is a question of occupation and management.

The ten years runs back from the date the Class Q development begins, not from the date of the application, which gives a small amount of planning room at the margin but not much.

And the restriction bites on any qualifying Part 6 development anywhere on the unit, rather than just on the building being converted. A new grain store at the far end of the holding can block the conversion of a redundant stone barn half a mile away.

Because the restriction works in both directions, a Class Q conversion also constrains later use of Part 6 on the same unit, so check the current text of both classes before planning a sequence of works.

Sequencing a building and a later conversion

Four options, and the right one depends on which asset matters more.

1. Convert first, then build under full planning permission. Where the barn conversion is the valuable move, take Class Q first and accept that the new agricultural building will need a planning application rather than prior notification. An agricultural building supported by a short justification of need, on an existing yard, is usually a straightforward application.
2. Build first, then convert in ten years. Where the farm needs the building now and the barn is not going anywhere, this works, but ten years is a long time to hold a development plan and the right itself may change in the interim.
3. Build first, then convert by full planning permission. A barn conversion outside Class Q is assessed against the local plan's rural conversion policies, which in many districts are supportive of the re-use of traditional farm buildings. This is the route most commonly overlooked, and in a conservation area or a National Landscape, where Class Q is unavailable anyway, it is the only route.
4. Do both under one planning application. Where the farm is restructuring, a single application covering the new building and the conversion gives the authority a complete picture and avoids the permitted development interaction entirely. It costs more in fees and takes longer, and it is the cleanest answer where both elements are needed.

Whichever route you take, the decision needs recording. Buyers' solicitors now ask about Part 6 development history on rural acquisitions, and a farm that cannot evidence what was built when has a problem at sale as well as at application.

Evidence of agricultural use and holding size

Both rights depend on facts that have to be proved, and the paperwork is the same for each.

Assemble the holding number and the mapped extent of the unit, farm business accounts covering the relevant years, subsidy and environmental scheme paperwork, livestock movement records, invoices for feed, seed, fertiliser and veterinary services, sales receipts, and dated aerial imagery showing the building in use. For Class Q, the critical date is the reference date in the Order, and evidence either side of it carries the most weight.

Statutory declarations from the farmer and from a neighbour or contractor are useful supporting material and are not a substitute for records. Authorities have become sceptical about declarations unsupported by anything contemporaneous.

Where the facts are at all arguable, a certificate of lawfulness under section 192 of the Town and Country Planning Act 1990 is the only formal way to confirm that a proposed use or operation is lawful. It costs a fee and several weeks, and it is considerably less expensive than building first and arguing later.

Conditions attached to each

Part 6 carries a condition restricting the use of development within 400 metres of a protected building for livestock or slurry, and a removal condition requiring the building to be taken down and the land restored where agricultural use ceases within ten years and no alternative permission follows within three.

Class Q development must be completed within a stated period from the date of prior approval, and the permitted works are limited to those reasonably necessary for the conversion. Authorities commonly attach conditions on materials, the curtilage boundary, access improvements and drainage.

Both sets of conditions reach forward in time, and both are enforceable. Read them before you build.

This is general guidance rather than legal advice, so check the position with your local planning authority or a qualified professional before relying on it. Where a full application is the better route, a Planning Statement addressing agricultural need, the re-use of a traditional building and the rural policy tests is the document the case officer reads first.

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