Worked example: sequential test for an edge of centre site

A sequential test worked example is more useful than another restatement of the policy, because the policy is short and the disputes are all about application. The test requires main town centre uses to be directed first to town centres, then to edge of centre locations, and only then to out of centre sites, with applicants expected to show flexibility on format and scale. Everything contested happens inside the words suitable and available.

The worked assessment below is illustrative. The site areas, floorspaces and conclusions are invented to show the method, and none of it is a precedent for a real scheme.

The limbs of the test and what they mean

Three questions have to be answered about every alternative site considered.

Availability asks whether the site could come forward within a reasonable period, which usually means within the development programme of the proposal rather than at some point in the plan period. A site in active use with an unexpired lease and no willing seller is not available, and saying so requires evidence rather than assertion.

Suitability asks whether the site is suitable for the development proposed. The Supreme Court in Tesco Stores Ltd v Dundee City Council settled that it means suitable for the development the applicant proposes, read with the duty to be flexible, and not suitable for some different development the authority would prefer. That distinction decides a great many appeals.

Viability sits slightly apart. It is not a separate statutory limb, but a site that cannot be developed at all is not realistically available, and where abnormal costs are relied on they have to be evidenced in the same way as in a Viability Assessment rather than asserted.

Defining the area of search

Get this agreed at pre-application stage, because an assessment of the wrong area is wasted work.

The search area is defined by the catchment the proposal is intended to serve, which for a mid-sized food store is usually a drive time or a defined primary catchment, and by the hierarchy of centres in the adopted plan. Start with the centres in the hierarchy that serve the catchment, work down the sequence, and include edge of centre locations around each.

Edge of centre needs a definition on the ground. National policy describes it as a location well connected to and within easy walking distance of the primary shopping area, with a 300 m walking distance commonly used as a starting point for retail. Measure it as an actual walking route rather than as a radius, because a site 250 m away across a dual carriageway with no crossing is not well connected.

A worked assessment of three candidate sites

The illustrative proposal: a 1,400 m2 gross convenience store with 90 parking spaces, on an edge of centre site 180 m from the primary shopping area of a market town, on a walking route with a signalised crossing.

Site A is the flexibility test. The applicant has to show that the format has been reduced and tested, rather than merely considered. In the illustration, a store of 1,000 m2 gross with 40 spaces was tested on Site A and rejected because the site cannot accommodate a service yard and a delivery vehicle turning area alongside any trading floor. That is a suitability finding supported by a drawing, which is the standard an inspector applies.

Site B is the servicing test, and it is the most common honest reason a town centre site fails. Record it with a swept path drawing, not a sentence.

Site C is the availability test. The evidence is the lease summary and correspondence with the owner, and without those two documents the conclusion is an assertion. An authority is entitled to reject an availability argument that rests on a telephone call nobody recorded.

Suitability, availability and flexibility in turn

For each site, the assessment should set out the physical constraints with a drawing, the planning constraints from the development plan and any designation, the ownership and lease position with documentary evidence, and the formats tested with areas and parking numbers stated.

Flexibility is where assessments are weakest. A proper demonstration shows at least two reduced formats tested against each sequentially preferable site, with the reason each was rejected. The reasons that carry weight are physical: insufficient depth for a sales floor plus back of house, no service access, a level difference that cannot be worked, a constraint on the site that cannot be designed out. The reasons that do not carry weight are commercial preference, a corporate store specification, and the absence of the applicant's standard parking ratio.

And there is a limit to flexibility. The policy does not require an applicant to abandon the development for which permission is sought, which is the practical effect of the Dundee reasoning.

Disaggregation and how far it goes

Disaggregation means splitting the proposal so that part of it could go to a sequentially preferable site, for example separating the comparison element from the convenience element of a store.

National guidance does not require applicants to disaggregate in every case. The question is whether it is practical in the particular circumstances, and the usual answer for a single food store is no, because the convenience and comparison elements share a single checkout operation, a single service yard and a single staff structure. Say that, with the operational reasoning, rather than ignoring the question. An assessment that does not mention disaggregation at all invites the authority to raise it.

Where the proposal really is a collection of separable units, the answer is different and the assessment has to deal with each unit.

Recording the assessment so it can be audited

The sequential assessment is the part of a retail submission most likely to be read by an inspector two years later, so write it to be checked rather than to persuade.

What a defensible record contains:

1. The date the search was carried out, and the date the information was refreshed before submission.
2. A plan of the search area with the centres and the edge of centre boundaries drawn.
3. A schedule of every site considered, including sites discounted at first sight, with the reason for discounting.
4. For each site taken forward, the evidence of availability, the formats tested and the drawings relied on.
5. The sources used, including the authority's own land availability assessment, commercial property listings and the local plan allocations, with dates.
6. A short conclusion that follows from the schedule rather than restating the proposal.

Stale evidence is the avoidable failure. A search carried out 18 months before submission will be attacked on the basis that a town centre site has since become available, so refresh it in the month before you submit and record the date.

Set the assessment out as a standalone Sequential Test (Retail) document, with the impact work in a separate Retail Impact Assessment where the floorspace threshold in the development plan is engaged. Defining the search area on a site with no obvious catchment is a harder exercise, and the approach is set out in the guide to defining a sequential test search area on a rural site.

This is general guidance, not legal advice, and every figure above is illustrative. Policy wording, local floorspace thresholds and centre boundaries change, so check the current position with your local planning authority or a qualified professional before relying on it.

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