Flexibility and disaggregation in the sequential test

The sequential approach for main town centre uses asks a narrow question: is there a town centre or edge of centre site that could reasonably accommodate the development. Everything contentious about the sequential test flexibility disaggregation argument flows from two words in that sentence. Flexibility means the applicant must be willing to adapt format and scale rather than insisting on a standard unit. Disaggregation means the authority may ask whether separable parts of the scheme could go to more central sites, but it cannot require a split that would make the proposal unworkable.

This is the retail and leisure test, not the flood risk one. Different policy, different evidence, same name.

What the sequential approach requires

National policy requires a sequential test for applications for main town centre uses that are neither in an existing centre nor in accordance with an up-to-date development plan. The order of preference runs from sites in a centre, to edge of centre sites, to out of centre sites, with preference among out of centre sites for those that are accessible and well connected to a centre.

Main town centre uses are defined in the Framework's glossary and reach wider than shops. Retail, leisure, entertainment, more intensive sport and recreation, offices, arts, culture and tourism development are all included. So a gym, a trampoline park, a cinema and a serviced office all engage the test, and operators regularly assume they do not.

There is no floorspace threshold for the sequential test. That is the impact assessment, which applies to retail and leisure development over 2,500 square metres gross outside a centre unless the development plan sets a different local threshold. An 800 square metre out of centre gym needs a sequential test and no impact assessment.

The current Framework was published on 17 August 2026 and uses policy codes rather than paragraph numbers, so take the code from the published document rather than reusing a reference from an older statement.

Defining the search area honestly

The search area follows the catchment the proposal serves, informed by the hierarchy of centres in the development plan.

A convenience store serving one neighbourhood has a small catchment and a short list of candidate centres. A retail park drawing from three towns has a large one, and searching only the nearest centre will not survive scrutiny.

Three things to settle at the start.

1. Which centres in the plan's hierarchy fall within the catchment, and the evidence for the catchment extent.
2. Whether edge of centre is being measured properly, which means walking distance from the primary shopping area or the centre boundary as defined in the plan, not a radius drawn on a map.
3. The date of the search, because availability changes and an old search invites a fresh one.

Agree the area with the case officer before the work is done. An unagreed search area is the cheapest ground of objection available to anyone opposing the scheme.

Flexibility on format, scale and car parking

Flexibility is the obligation that applicants resist and authorities over-apply.

What it properly requires is a willingness to consider a different building form, a smaller floorplate, a split-level unit, a reduced or shared car park, servicing from a different arrangement and a different mix of floorspace. An operator who says the scheme only works as a single-storey 1,200 square metre box with 60 surface spaces has not demonstrated flexibility.

What it does not require is a different type of development, or a scheme so altered that it no longer meets the need identified. National guidance is clear that the test should be applied proportionately and should not be used to prevent competition between operators.

Car parking is where the argument usually lands. A town centre site with public car parks nearby can serve a use that does not need dedicated spaces, and the applicant has to engage with that rather than dismissing it. Equally, a use with genuine servicing requirements, such as a trade counter with regular deliveries by articulated vehicle, has a real constraint and should evidence it with swept paths rather than assertion.

Disaggregation and its limits

Disaggregation asks whether parts of a proposal could be accommodated separately on more central sites. It applies most obviously where a scheme bundles distinct components: a food store with a separate non-food element, a leisure scheme with a restaurant terrace, an office with a trade counter.

The limits matter as much as the principle. Guidance does not require an applicant to demonstrate that a scheme could be broken into pieces regardless of consequence, and a split that would make the proposal unviable or unworkable in operation is not a reasonable ask. Shared servicing, shared staffing, a single customer trip and an integrated design are all legitimate reasons why components belong together.

So the answer in a strong statement is not refusal to engage. It is to identify the components honestly, test the separable ones against central sites, and explain with evidence why the remainder cannot be split.

Where viability is put forward as the reason, expect it to be examined, and expect the authority to treat an unevidenced viability assertion with the same scepticism it applies elsewhere. The way that scrutiny plays out is set out in when an inspector reopens viability at appeal.

Site availability, suitability and viability

Three filters, applied in that order, and each needs its own evidence.

Suitability is about whether the site could accommodate the development with the flexibility described above. It is not about whether it suits the operator's preferred specification. Site constraints, access, levels, ownership fragmentation and designations are all legitimate suitability points if evidenced.

Availability is about whether the site is available within a reasonable period, having regard to the timescale of the development. A site under offer to another party, in active use with an unexpired lease, or subject to an allocation for a different use, may not be available. The evidence is marketing particulars, agents' correspondence, title information and site inspection records.

Viability has the narrowest role. It is relevant to whether a site could realistically be developed at all, rather than to whether the applicant would prefer a cheaper site. Keep it short and evidenced, and do not use it as a catch-all reason for discounting everything.

Documenting the search

The document that works is unglamorous and auditable.

Set out the proposal and why the test applies, the catchment and the centres within it, the sources searched with dates, a plan showing every site considered with its centre status marked, and a table with one row per site giving area, centre status, ownership, availability evidence and the reason for discounting. Then the conclusion, and a short statement of the flexibility that was applied.

Keep it as a standalone Sequential Test document rather than a chapter inside something else, so that a consultee or a member can find it. Where the impact threshold is also crossed, the Retail Impact Assessment sits alongside it and answers a different question about trade diversion and the health of the centre.

A Planning Statement then draws the policy thread together, and where employment or investment benefits form part of the case, an Economic Impact Assessment carries that evidence rather than leaving it as assertion in a covering letter.

Common failures at appeal

Five patterns recur, and inspectors' decisions on them are indicative of the approach rather than binding precedent.

The applicant tested central sites against the exact proposed scheme, rejected them for not fitting, and called that flexibility. The search area was drawn to exclude a centre with available sites. Sites were discounted because the applicant did not own them or could not agree a price. The operator's standard format was treated as a fixed requirement. And the test was skipped altogether because the plan was said to be out of date, without checking whether the proposal accorded with an up-to-date policy.

The fix for all five is the same. Do the test before the design is fixed, so the answer can change the scheme rather than having to defend it.

To see which commercial and town centre documents your proposal is likely to need, enter your postcode on PlanScope and work through the guided questions. Councils expect suitably qualified authors for retail and economic evidence, and professional review is strongly advised.

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.