Part 3 Class N: amusement arcades and casinos to housing

Class N of Part 3 is the permitted development right that turns an amusement arcade, an amusement centre or a casino into dwellings, subject to prior approval and a floorspace cap of 150 m². It exists because these uses are sui generis, outside the use classes, so the commercial to residential route under Class MA does not reach them. If you are looking at a shuttered seafront arcade or a small former casino unit, Class N is the only permitted development option on the table.

One hundred and fifty square metres is not much. Think one or two flats, not a block.

What Class N permits and its floorspace limit

The class permits a change of use of a building, and any land within its curtilage, from use as an amusement arcade or centre, or as a casino, to use as dwellinghouses within Class C3. It also permits the building works reasonably necessary to convert, which is important because the pure change of use right in the earlier parts of the Order does not cover physical works.

The cumulative floorspace of the building changing use must not exceed 150 m². That is measured across the whole building, so a ground floor arcade of 140 m² with a 40 m² first floor office in the same planning unit is outside the right on the arithmetic alone.

Works reasonably necessary to convert covers internal alterations, new windows and doors in existing openings, insulation, services and the external changes the conversion needs. It does not cover extensions, additional storeys, or alterations that go beyond conversion into remodelling. Where the scheme needs more than that, the application is a full planning application supported by a Planning Statement rather than a prior approval.

Prior approval matters the authority considers

The authority's consideration is limited to the matters the class lists. It cannot refuse prior approval because it would prefer the arcade to continue, or because it dislikes the residential use in principle, or because a policy in the local plan resists the loss of that use. The list is the list.

Those matters cover transport and highways impacts, contamination risk, flooding risk, the impact of noise from nearby commercial premises on the intended occupiers, and the design and external appearance of the building in relation to the proposed works. Read the current text of Class N before you prepare the submission, because Part 3 has been amended repeatedly and the matters for consideration vary between classes within it.

Each listed matter needs a document. An authority that receives a bare application form will ask for them, and the 56-day period does not start until the application is complete.

Noise, contamination and flooding in a town centre unit

The noise matter is the one that usually decides a Class N application, because arcades sit in commercial frontages next to pubs, takeaways, plant and late-night servicing.

The assessment has to look outward at the existing commercial environment and ask whether the new residents will have acceptable internal conditions. That means a baseline survey covering the hours when the noise actually occurs, usually late evening and early morning, assessed against internal criteria for bedrooms and living rooms, with the mitigation specified as glazing and acoustically attenuated ventilation rather than as a promise. A Noise Impact Assessment prepared on that basis answers the matter directly. One that measures a Tuesday afternoon does not.

Contamination risk on a town centre arcade is usually low, but the building history is not always as dull as it looks. Former petrol filling, garage, workshop or printing uses on the same footprint, or a basement with tanks, all push the assessment towards a preliminary risk assessment and sometimes intrusive work. A desk study and a conceptual site model usually discharge the matter, and the land contamination assessment is the document the authority expects.

Flooding risk in a seafront or riverside arcade is often the harder one. Ground floor residential in Flood Zone 3 engages the vulnerability classification, and a prior approval does not sidestep the flood risk policy tests, so a site in a higher zone may be unviable as ground floor housing whatever the right says.

Evidence of the lawful previous use

The class fixes a baseline: the building must have been in the qualifying use on a specified date set out in the class, or when it was last in use before that date. Establishing that is the applicant's job, and it is where these applications fail quietly.

Useful evidence, in rough order of weight:

• A planning permission or lawful development certificate for the arcade or casino use.
• A premises licence or gaming licence naming the operator and the address, with dates.
• Business rates records showing the description and the rateable period.
• Leases, licences and operating agreements with dates and the permitted user clause.
• Dated photographs, signage, trade directory entries and local newspaper advertising.
• A statutory declaration from the operator or landlord, as support rather than as the primary evidence.

A gap in the record is not fatal, but it has to be explained. The same evidential discipline that governs agricultural buildings applies here, and the approach set out in proving the building was in agricultural use under Class Q transfers almost directly.

Exclusions, and the conditions that follow approval

Class N does not apply to every building. Listed buildings and scheduled monuments are outside it, and the class carries the usual exclusions for sites of special scientific interest, safety hazard areas and military explosives storage areas. Check the designations on the national mapping services before you spend money on drawings.

Where prior approval is granted, the development has to be completed within the period the class specifies, which is measured from the date of approval. Diary it. An approval that lapses before the conversion is finished leaves the building in an awkward position, with part of the works done under a right that no longer has effect.

Where Class MA applies instead, and when to go for permission

Class MA covers change of use from Class E, the commercial, business and service class, to dwellinghouses. An amusement arcade is sui generis, so it is not in Class E and Class MA is unavailable. If the building has been used for something within Class E since the arcade closed, however, the picture changes, and the vacancy and continuous use requirements in Class MA vacancy and continuous use conditions become the relevant test instead.

Go for full planning permission where the floorspace exceeds 150 m², where extensions or additional storeys are needed, where the building is listed, or where the noise and flood position means the scheme only works with a layout change the right cannot deliver. A full application also lets you argue the planning merits, which a prior approval application does not, and in a town centre with a vacant frontage those merits are often better than applicants expect.

Building Regulations apply either way, and they are the real constraint on a 150 m² conversion. Sound insulation between dwellings, means of escape from a single-stair layout above a commercial ground floor, ventilation, overheating under Approved Document O and the energy standards all have to work in a building that was designed as one open hall with few windows. Resolve that before submitting, because a scheme that cannot meet Part B is not deliverable however the planning route goes.

Enter the postcode on PlanScope to see the constraints recorded against the building and which of the 66 report types the prior approval matters are likely to require.

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