Strategic gaps and green wedges as local designations

A strategic gap policy for development purposes is a local plan designation protecting the open land that keeps two settlements from merging. It has no statutory basis and no national policy behind it, which means the wording of the policy in the adopted plan is the entire test. There is no equivalent of the Green Belt's definition of inappropriate development and no very special circumstances hurdle to clear.

That sounds like an easier proposition than Green Belt, and sometimes it is. But a gap policy in an up to date plan carries full weight under section 38(6) of the Planning and Compulsory Purchase Act 2004, and the argument turns on landscape evidence rather than on a policy exception you can point at.

Where these designations come from

Strategic gaps, local gaps, green wedges and countryside gaps all do the same job under different names. They appear in local plans where two or more settlements have grown towards each other and the authority wants to keep a physical and visual break between them.

The designation is normally supported by an evidence base prepared for the plan: a settlement separation study, a landscape sensitivity or capacity assessment, sometimes a specific gap study that defines the boundary and states the purpose of each gap. That evidence matters more than the policy text, because it tells you what the authority thought the gap was for and which parts of it carry the separation function.

Green wedges tend to be described differently again, as green corridors running into an urban area with a recreational and ecological role as well as a separation role. Where the policy names those additional purposes, the assessment widens to cover them.

Read the plan's supporting text and the evidence base before you read the policy. The difference between a gap justified by intervisibility and a gap justified by remaining distance changes which site within it is defensible.

Status compared with Green Belt

The two are routinely conflated in objections, and the differences are worth stating plainly.

The practical consequences are two. First, a strategic gap has no closed list of exceptions, so the argument is about effect rather than about category, and a well-designed scheme can succeed on its merits in a way it could not in the Green Belt. Second, weight is vulnerable. Where the plan is old or the authority cannot demonstrate its housing land supply, the gap policy is among the policies whose weight can be reduced, and the balance tilts.

A site can of course be in both. Where it is, the Green Belt test is the harder one and the gap argument follows it rather than leading. Our note on evidencing Green Belt openness in a planning application sets out how the openness question is approached there.

The coalescence argument and how it is tested

Coalescence is the merging of two settlements into one, in fact or in perception. The test an inspector applies is whether the proposal would materially reduce the separation the gap exists to protect.

Four factors do most of the work. The remaining distance between the built edges of the two settlements after development, measured along the route someone would travel between them. Whether the two settlements would become intervisible from that route where they are not now. Whether the development would read as part of one settlement extending towards the other, or as a discrete element within open land. And whether the landscape framework that gives the gap its character survives.

The perception point deserves attention, because it is where objections are strongest and where evidence is weakest. A traveller's experience of leaving one place and arriving at another depends on a sequence of views over a distance, not on a single photograph. Sequential assessment along the connecting road or railway is far more persuasive than isolated viewpoints, and it is what an inspector will ask for at a hearing.

Appeal decisions on gap policies are useful for seeing how inspectors have approached these factors, and they are indicative rather than binding. The policy wording differs between authorities, so a decision on one authority's gap does not settle another's.

Landscape and visual evidence that matters

This is a landscape case, and it needs landscape evidence rather than planning assertion.

A Landscape and Visual Impact Assessment prepared to GLVIA3 principles is the core document. Councils usually expect a suitably qualified author, so professional review is strongly advised. What makes it useful on a gap case rather than generic is a set of additions.

Include a settlement edge analysis showing the existing built edges of both settlements and how they are formed. Include a plan of remaining separation distances before and after, with the measurement route shown. Include a zone of theoretical visibility and then sequential viewpoints along the connecting route, with photomontages at the points where the two settlements could come into the same view. And include an assessment against the stated purposes of the gap in the adopted policy, purpose by purpose.

Where the policy's own evidence base identified the parts of the gap that carry the separation function, map your site against that. A site the authority's own study described as visually contained is a different proposition from one it described as the narrowest point.

The treatment of views matters here in the same way as it does under an express view protection policy, and our note on protected views and viewing corridors in decision taking covers how those are assessed.

Development sometimes found acceptable

Gap policies vary, and so do outcomes. The patterns that succeed share a characteristic: the openness and the perception of separation survive.

Uses that often work include outdoor sport and recreation with modest built form, allotments, cemeteries, agricultural and forestry buildings, and reversible uses such as some renewable energy schemes where the land can return to its former state. Small-scale infill within an existing built group, where the group already interrupts the gap, is frequently accepted.

Built development succeeds most often where it sits against an existing settlement edge, is contained by landform or existing vegetation, does not extend along the connecting road, and is accompanied by a landscape scheme that strengthens the gap elsewhere. Ribbon development along the road between two settlements is the pattern that fails most reliably, because it creates exactly the continuous frontage the policy exists to prevent.

A Landscape Strategy offering positive management of retained gap land, secured for the long term, is worth more than a generic planting plan. Where the scheme can leave the gap functioning better than it does now, say so and back it with a mechanism.

Challenging a boundary at plan review

Gap boundaries are drawn and redrawn through the local plan process, and that is the proper place to argue about them.

The soundness tests give you the framework. A gap boundary has to be justified by proportionate evidence and consistent with national policy, so a boundary drawn to a field edge with no separation function, or drawn far wider than the evidence supports, is open to challenge. Representations at the consultation stages, followed by participation at examination, are the route.

What works in a representation is evidence, not objection. Commission the landscape work, show which part of the gap does the separation job, and propose an alternative boundary with reasons. Authorities and inspectors respond to a mapped alternative far better than to an argument that the designation is unnecessary.

If the plan is near adoption, this route is closed for several years, which is worth knowing before the site is bought.

Structuring an application

Order the case so that the gap argument comes early and is answered on its own terms.

1. Quote the policy in full and list its stated purposes.
2. Address each purpose separately with evidence, rather than making one general case about landscape quality.
3. Give the separation distances before and after, with the measurement route.
4. Present the sequential visual assessment, not a single viewpoint.
5. Set out what the scheme does for the retained gap land and how that is secured.
6. Deal with weight: the plan's age, the housing land supply position, and whether the policy is consistent with national policy.
7. Only then turn to the planning balance and the benefits.

A Planning Statement that follows that order tends to survive committee, because it gives the officer a purpose-by-purpose answer to quote. One that leads with housing need and mentions the gap in a closing paragraph does not.

Enter your postcode on PlanScope to see which landscape and planning documents a constrained edge-of-settlement site is likely to need.

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