Material change of use under section 55
A change of use needs planning permission only if it is material, and materiality turns on the character of the use rather than the occupier or the trading name.
A material change of use is a change in the character of how a building or piece of land is used, substantial enough to count as development under section 55 of the Town and Country Planning Act 1990. Get that judgement wrong and you are trading without permission. Get it right and you may need nothing at all. The material change of use test in planning law does not turn on who occupies the premises, what the lease permits or what the business is called over the door. It turns on the character of the use, judged as a question of fact and degree.
That is an uncomfortable answer for anyone about to sign a lease. It is also the honest one.
The statutory definition of development
Section 55(1) divides development into two limbs. The first covers operations: building, engineering, mining and other operations in, on, over or under land. The second covers the making of any material change in the use of any buildings or other land. The Act offers no further definition of the word material, and that silence is deliberate. Parliament left the line to be drawn case by case by councils, inspectors and the courts.
Two practical consequences follow.
A change of use needs no physical works to be development. A unit trading as a florist on Friday and as a tattoo studio on Monday has developed the land even though nobody lifted a hammer. Equally, expensive works can leave the use untouched, so a full refit of a shop that stays a shop is not a change of use at all.
Section 55(3)(a) settles one argument by statute rather than by judgement. Using a building previously occupied as a single dwellinghouse as two or more separate dwellings involves a material change of use of the building and of each part of it. There is no room to argue fact and degree on that one.
What makes a change material rather than trivial
Materiality is assessed in planning terms, which is narrower than it sounds. The case officer is asking whether the change brings planning consequences: vehicle movements, hours of operation, noise, odour, refuse, servicing, the effect on neighbouring occupiers, the effect on a shopping frontage. A change that alters none of those is unlikely to be material, however different the trade looks from the pavement.
Section 55(2) puts several things outside development altogether, which is where many arguments end before they start.
| What section 55(2) excludes | Practical effect |
|---|---|
| Internal works, and external works not materially affecting external appearance | Fit-outs and internal reconfiguration are not operational development |
| Use of land or buildings within the curtilage of a dwellinghouse for a purpose incidental to its enjoyment | Home offices, hobby workshops and garden stores stay outside control while the use stays incidental |
| Use of land for agriculture or forestry, and of buildings occupied with that land | Farming operations sit outside the definition, though buildings still need their own consent |
| A change to another purpose within the same class of the Use Classes Order | Movement inside Class E needs no permission |
That last line is the one commercial occupiers reach for most. Class E of the Town and Country Planning (Use Classes) Order 1987, as amended in 2020, gathers shops, financial and professional services, cafes and restaurants, indoor sport, medical uses, creches, offices, research and light industry into a single class. Moving between them is not development. Moving out of Class E to something sui generis, a hot food takeaway or a drinking establishment for instance, is a different matter entirely.
Character of the use as the test
The leading authority is still East Barnet Urban District Council v British Transport Commission, decided in 1962, where land beside a railway moved from coal storage to the storage of crated vehicles. The court held that what mattered was whether the character of the use of the land had changed, not the identity of the goods or the occupier. Storage remained storage.
Apply that honestly and some intuitive answers fall over. A change from a bookmaker to a nail bar feels dramatic and may well be immaterial in planning terms. A change from an office with eight staff to an office with eighty may feel like more of the same and be plainly material.
The unit being assessed matters as much as the use. Courts apply the planning unit approach set out in Burdle v Secretary of State for the Environment (1972), which looks for the unit of occupation where there is a single main purpose with activities ancillary to it, and treats physically separate areas in substantially different and unrelated uses as separate units. Where an ancillary activity grows until it is no longer subordinate, a new use has arrived inside the same four walls.
Intensification and where it crosses the line
Doing more of the same can be development. The courts accept that intensification may amount to a material change of use where the degree of change alters the character of the use, while cautioning that it remains a question of fact and degree with no arithmetic threshold.
Houses in multiple occupation show the principle written into the Use Classes Order. A dwellinghouse occupied by a single household is Class C3. A small shared house of between three and six unrelated occupiers sharing facilities is Class C4. More than six occupiers and the use falls outside both classes as sui generis. Many councils have also made Article 4 directions removing the permitted change from C3 to C4 in defined wards, so the same conversion needs permission in one street and not in the next.
For a business the usual triggers are hours, deliveries, staff numbers, customer numbers and the balance between two activities on one site. A cafe selling a few sandwiches to take away is still a cafe. When most of the food leaves the premises, the character has moved towards a takeaway and the use has probably changed.
Evidence councils look for
Officers assess character on evidence, and the applications that stall are the ones that supply assertions instead. Expect to provide most of the following.
- Floor plans with areas in m², showing the split between customer, preparation, storage and staff space.
- Proposed hours of opening, and hours for deliveries and waste collection separately.
- Staff numbers by shift and expected customer numbers at peak.
- Vehicle movements, including servicing, and where vehicles will stand.
- Waste storage and collection arrangements.
- Any plant, extraction or refrigeration, with its location and acoustic data.
- For a mixed operation, the proportion of turnover or floorspace attributable to each activity.
Where the proposal brings environmental effects, the supporting documents follow from those effects rather than from the label on the application. The full set of report types shows which evidence tends to attach to which issue, from extraction and odour through to parking and noise. A short Planning Statement that walks the officer through the character test, with the numbers behind it, is worth more than a long one that recites policy.
Getting the position confirmed
Nothing said by an officer on the telephone binds the council. The only formal route to certainty is an application for a lawful development certificate: section 191 of the 1990 Act for a use already in existence, section 192 for one proposed. The certificate answers a legal question rather than a planning merits question, so the council cannot refuse it because the use would be unneighbourly. Fees for the two routes differ and are set by national regulations, so check the current fee schedule before you submit.
Councils have eight weeks to determine a certificate application for most cases. Where nothing arrives by the deadline you have a right of appeal against non-determination, and the practical trade-offs in that decision are set out in our note on the deemed refusal appeal. Refusals attract a right of appeal to the Planning Inspectorate on the same legal question.
One honest caveat. Certificates are decided on the evidence put in front of the council, so a thin application can produce a refusal on a use that was lawful all along. Statutory declarations, dated invoices, utility bills, photographs and staff records carry weight. Recollection does not.
This is general guidance, not legal advice; 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.
Enter your postcode on PlanScope to see which reports your site is likely to need before you commit to a change of use.
Frequently asked questions
Does a change of use always need planning permission?
No. Permission is needed only where the change is material, meaning the character of the use alters in planning terms. Movement between purposes inside the same class of the Use Classes Order is excluded by section 55(2)(f), and several other categories sit outside the definition of development. Where the position is doubtful, a lawful development certificate settles it.
How do I know if a change is material or trivial?
Ask what changes on the ground: hours, traffic, deliveries, noise, odour, waste, customer numbers and the effect on neighbours. If none of those shift, the change is unlikely to be material. If several shift markedly, it probably is. The test is one of fact and degree, so there is no fixed threshold to apply.
Can doing more of the same use need permission?
It can. Intensification amounts to a material change of use where the increase alters the character of the use rather than simply its volume. A home business that grows into a depot with daily deliveries is the standard illustration. Courts have declined to set a numerical trigger, so councils assess each case on its own evidence.
What is a lawful development certificate and when should I apply?
It is a formal determination that a use is lawful, applied for under section 191 for an existing use or section 192 for a proposed one. Apply before signing a lease, before selling, or where a council has queried what you are doing. The council decides a legal question, so planning merits are irrelevant to the outcome.
Does splitting a house into flats count as a material change of use?
Yes, by statute. Section 55(3)(a) of the Town and Country Planning Act 1990 states that using a building previously occupied as a single dwellinghouse as two or more separate dwellings involves a material change of use of the building and of each part of it. There is no argument about fact and degree available.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.