The retail sequential test: available, suitable and viable

The retail sequential test is three questions asked of every alternative site, and losing an appeal on it almost always means one of the three was answered loosely. Is the site available. Is it suitable. Is it viable. National policy requires main town centre uses proposed outside a town centre to demonstrate that there are no suitable sequentially preferable sites, and Planning Practice Guidance frames that demonstration around those three limbs.

The current National Planning Policy Framework, published on 17 August 2026, carries its town centre policies as policy codes rather than the paragraph numbers used in earlier editions. Check the code in the edition you are working from, because an inspector will.

Where the test comes from

National policy applies a town centre first approach. Main town centre uses should be located in town centres, then in edge of centre locations, and only then out of centre, with preference among out of centre sites for those that are accessible and well connected to the centre.

The test applies to applications for main town centre uses that are not in an existing centre and are not in accordance with an up-to-date development plan. An allocation in an adopted plan does the work for you, which is the first thing to check before commissioning any search.

Separately from the sequential test, an impact assessment is required for retail and leisure development outside town centres above a floorspace threshold. Where the plan sets no local threshold, the national default of 2,500 m² applies. Local plans frequently set lower figures, and in a district with a 500 m² threshold the assessment burden on a mid-sized scheme is entirely different.

Defining the catchment and the centres to search

The search area is where arguments start. Define it with evidence rather than assertion.

Begin with the centre hierarchy in the development plan, then identify which of those centres could realistically accommodate a development of the type and scale proposed. A district centre with a 1,200 m² vacant unit is a candidate for a 1,000 m² foodstore and is not a candidate for a 6,000 m² one.

Three practical points.

The catchment should reflect how the proposal would actually trade, supported by drive time or walking distance analysis, not by a convenient administrative boundary.

Centres in neighbouring authorities count if they fall within the catchment. Omitting them because they sit over a border is the most common structural error in a sequential test, and objectors notice.

The search has to be current at the date of the decision, not the date it was written. A search eight months old will be attacked, and on a long determination it should be refreshed.

Availability and the timing question

Available means available for the development, now or within a reasonable period. Reasonable has no fixed definition, and that is where judgement enters.

Evidence availability properly:

• Named agent enquiries, with dates, and the response recorded.
• Ownership position, including whether the owner is willing to sell or let.
• Existing occupation, lease terms and break dates where known.
• Any allocation, option or conditional contract affecting the site.

A site in active occupation under a lease with eight years to run is not available in any meaningful sense, and saying so with the lease position evidenced is far stronger than asserting it. Conversely, a vacant unit whose owner has refused to engage is still available unless you can show why not.

The timing question cuts both ways. A town centre site that will come forward in three years may be sequentially preferable for a plan-led scheme and not for an occupier with a committed requirement, and the inspector will want to know which situation this is.

Suitability and the flexibility you must show

Suitability is judged against the development proposed, not against some hypothetical alternative scheme. The Supreme Court settled that in Tesco Stores Ltd v Dundee City Council, and it is the most frequently cited authority in this area.

That does not let an applicant define the proposal so tightly that no other site could ever accommodate it. National policy requires applicants to demonstrate flexibility on format and scale, so a search that rejects every alternative because it cannot take the exact floorplate, the exact car parking ratio and the exact servicing arrangement will fail.

The balance an inspector looks for:

Disaggregation deserves its own sentence. There is no requirement to split a proposal across several sites where doing so would not be practical or viable, and the courts have accepted that. But the applicant has to explain why, in terms specific to the operation rather than in general.

Viability as the third limb

Viability here means the viability of developing the alternative site for the proposal, assessed on normal development appraisal principles. A site that could physically take the scheme but only at a cost that no operator would bear is not a sequentially preferable site.

Two cautions. First, viability evidence in a sequential test is not the same exercise as a Viability Assessment testing affordable housing or obligations, although the appraisal discipline overlaps. Second, an unsupported assertion that an alternative site is unviable carries no weight. Show the abnormal costs, the site assembly position or the remediation liability that makes it so.

Where the alternative site is in the same ownership as a landowner with no intention of selling, that is an availability point rather than a viability one. Keeping the three limbs distinct in the write-up is what makes the search legible.

Edge of centre and the 300 metre question

Edge of centre has a defined meaning in the Framework's glossary. For retail purposes it is a location well connected to and up to 300 metres from the primary shopping area. For all other main town centre uses it is a location within 300 metres of a town centre boundary.

Two consequences follow. A site at 280 metres with a severance feature between it and the centre, such as a dual carriageway with no crossing, may be edge of centre on the measurement and function as out of centre in practice. And a site at 350 metres is out of centre however good the footpath link, which affects the order of preference in the search.

Measure from the right boundary, state which boundary you measured from, and show the route rather than the straight line distance.

Presenting a search that holds up

Structure the document so the reader can audit it. A table of every centre in the catchment, a table of every site considered in each centre, and three columns recording the conclusion on availability, suitability and viability with the evidence reference for each.

Then deal with the near misses honestly. Every sequential test has one or two sites that are arguable, and addressing them head on with the evidence is more persuasive than burying them in a list.

A Sequential Test (Retail) draft structures that search and the policy framing, and an Economic Impact Assessment often sits alongside it where regeneration or employment benefits form part of the case. Councils normally expect a suitably qualified author for retail impact work, and professional review is strongly advised.

Enter your postcode on PlanScope to see which reports a retail or leisure proposal outside a centre is likely to need.

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.