When intensifying a use needs planning permission

More of the same use can still be development. Intensification of use planning permission is needed where the increase in activity has changed the character of the use, which is a question of fact and degree rather than a line in a table. Doubling your covers, adding a second shift, taking deliveries at 6am instead of 10am, letting a trade counter turn into a shop open to the public: each of those can tip a lawful use into a material change of use under section 55 of the Town and Country Planning Act 1990.

There is no percentage that triggers it. Councils and inspectors look at what the operation has become, compared with what it lawfully was.

When more of the same becomes development

Section 55 defines development to include a material change in the use of buildings or other land. The courts have long held that intensification by itself is not automatically a material change, because the use may simply be busier. What counts is whether the character of the use has altered.

A useful way to think about it is to describe your operation in one sentence as it was when permission was granted, then describe it as it is now, and see whether the two sentences name the same thing. A workshop making bespoke furniture for trade customers that now sells finished pieces to the public from a showroom has become something else. A workshop that makes more furniture has not.

The planning unit matters too. The approach the courts take asks whether the occupier uses the whole site for a single main purpose, with other activities ancillary to it, or whether physically distinct parts are used for substantially different and unrelated purposes. Where an ancillary activity grows until it stands on its own, you may have created a second planning unit, and that is a material change even if the floorspace never moved.

How character is judged in practice

Officers assess character through effects. The things that get written into a report are hours of operation, the number of customers or visitors, staff numbers, vehicle movements, delivery frequency and timing, plant running hours, external storage, waste volumes and noise at the site boundary.

None of those is decisive alone. Together they paint the picture an officer uses to decide whether the use is recognisably the one that was permitted. A gym that opened 7am to 9pm with 40 members at a time and now runs 5am to 11pm with classes on the hour has changed in a way an officer can describe without reaching for a percentage.

Use class gives you less protection than people assume. Movement within Class E does not require permission, and a Class E unit can shift between a shop, a café, an office and a gym freely. But Class E says nothing about scale or hours, and an intensified Class E use can still be a material change if its character has altered. The flexibility is about category, not about how hard you run the building.

Evidence that settles the argument

Whichever side of the argument you are on, the evidence is operational data rather than opinion.

• Till or booking records showing customer numbers by hour and by day over a run of months
• Staff rotas going back through the period in dispute
• Delivery notes, haulier schedules and gate logs
• A plant inventory with running hours and any sound data from the equipment schedules
• Floorspace plans showing what each area is used for, and which parts are ancillary
• Any conditions on the original permission, and whether they have been complied with

Where a transport question arises, a short Transport Statement built from your own arrival data is more persuasive than a national trip-rate figure, because the officer can see the actual pattern. The same is true of sound. A Noise Impact Assessment that measures your plant and your deliveries at the nearest house answers the complaint directly, and councils expect a suitably qualified author for that work.

Complaints, and what the council can do

Intensification rarely surfaces through a planning officer noticing. It surfaces because a neighbour complains about deliveries at dawn or a chiller fan at night, and enforcement picks it up.

The authority's first move is usually informal. If that goes nowhere it can serve a planning contravention notice under section 171C of the 1990 Act, which requires you to give information about the use of the land and about activities on it. Answering it accurately matters, because failing to respond is an offence and a false answer is worse. From there the options are an enforcement notice under section 172, a breach of condition notice under section 187A where a condition has been broken, or in serious cases an injunction.

The practical risk is not usually a notice. It is a stop on expansion while the position is argued out, and that costs more than the application would have.

Establishing the lawful level of activity

Before you can say whether activity has intensified, you need to know what was lawful. Pull the planning history for the unit, read every condition on every permission, and check whether an earlier permission was implemented in full.

Conditions are where the surprises sit. Older consents frequently limited hours, restricted sales to trade only, capped the number of covers, or tied the use to a named occupier. A condition restricting retail sales to goods manufactured on the premises still binds you decades later unless it has been varied or has lapsed on its own terms.

Where the record is thin, a certificate of lawfulness of existing use or development under section 191 of the 1990 Act is the formal route to pin it down. That takes dated, independent evidence rather than recollection.

Regularising what you already do

If the honest conclusion is that the operation has moved beyond its permission, there are two routes.

1. Apply for planning permission for the change of use, describing the operation as it actually runs. The description of development is the thing to get right, because it defines what you are permitted to do.
2. Apply under section 73 of the 1990 Act to vary or remove a condition that no longer fits, where the use itself is lawful and only a condition is in the way.

The second is usually faster and costs less, and it leaves the underlying permission intact. It only works where the condition is the problem. Section 73 cannot be used to change the description of development itself.

Either way, lead with the evidence on effects. An application that says "the use already operates at this level and here is the data showing what that means at the boundary" is a different proposition from one that asks for an open-ended increase.

Conditions that fix the activity level

Councils grant intensification applications far more readily when the permission pins the operation down. Offer the conditions rather than waiting for them.

Workable ones include opening hours by day of the week, delivery and servicing hours, a cap on plant running hours, a sound limit expressed as a rated level at a defined assessment position, a waste and refuse management scheme, external storage restrictions, and a travel plan or parking management scheme where arrival patterns are the issue. Where extraction is involved, a condition requiring the installation to be built and maintained to an approved Ventilation and Extraction Statement is standard.

Conditions capping customer numbers look attractive to objectors and are hard to enforce, so officers often resist them. A condition on hours and on measurable effects does the same job and survives scrutiny better. All conditions have to pass the six tests in the Planning Practice Guidance on conditions, which means necessary, relevant to planning, relevant to the development, enforceable, precise and reasonable in all other respects.

PlanScope can draft the planning statement and the supporting documents for a change of use or a section 73 application, structured to UK planning policy, with gaps flagged where your own operational figures need to go in. Enter your postcode on PlanScope to see which reports your site is likely to need. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.