Benchmark land value: what it means in planning

Benchmark land value is the figure a viability assessment uses to represent what the land is worth to the person who owns it, and everything else in the assessment is tested against it. National guidance sets it as the existing use value of the land plus a premium for the landowner. The price the developer actually paid does not come into it, and a council is entitled to disregard an overpayment entirely.

That last sentence is the whole argument in most viability disputes, and it is the part objectors are rarely told.

What the term means

A viability assessment works out whether a scheme can carry the affordable housing, section 106 contributions and other policy requirements the development plan asks for. It does this by taking the value of the finished development, subtracting build costs, fees, finance and a developer's return, and seeing what is left for the land.

If the residual figure is above the benchmark, the scheme is viable with policy compliance. If it falls below, the applicant argues that something has to give, and the something is usually affordable housing.

So the benchmark is the dividing line. Set it high and almost any scheme looks unviable. Set it at existing use value alone and few landowners would ever sell. The guidance puts it in between, deliberately.

Where it comes from in policy

Benchmark land value is defined in the Planning Practice Guidance chapter on viability, which sits alongside the National Planning Policy Framework. The guidance says the benchmark should be established on the basis of the existing use value of the land, plus a premium for the landowner, and that the premium should give a reasonable incentive for the owner to bring the land forward while allowing the scheme to meet policy requirements in full.

Three points in that guidance do most of the work in practice. The benchmark must be based on policy-compliant development, so the assessment cannot assume a scheme with less affordable housing and then claim the land is worth more. The price paid for land is not a justification for failing to comply with policy. And viability should normally be tested when the local plan is prepared, with site-specific assessment reserved for cases where particular circumstances justify it.

The Royal Institution of Chartered Surveyors also publishes a professional statement on assessing viability in planning, which binds its members on matters such as independence, assumptions and reporting. Where a viability assessment is prepared by a chartered surveyor, that statement applies to it.

The guidance also treats viability assessments as public documents. Councils publish them, with narrow exceptions, so an objector can usually read the inputs rather than guess at them.

How decision makers apply it

The existing use value is the value of the land in its current lawful use, assuming no planning permission for the new scheme. A field in agricultural use is valued as a field. A working depot is valued as a depot, including the income it produces.

The premium sits on top. It is a matter of judgement, informed by evidence of what landowners in the area have actually accepted, and it is where most disagreement lands. Councils commonly instruct their own surveyor to review the applicant's figure, and the cost of that review is often paid by the applicant under an agreed arrangement.

An alternative use value may be used instead of existing use value where there is an existing permission for that alternative use, or a realistic prospect of one, and where that alternative would itself comply with policy. A warehouse with an unimplemented permission for offices might be valued on the office basis. A warehouse whose owner merely hopes for housing consent is not.

On the cost side, the guidance indicates that a return to the developer of between 15 and 20 per cent of gross development value may be considered a suitable figure, with a lower return potentially appropriate for build to rent and for the affordable housing element. Those percentages are among the few numbers national guidance actually supplies, which is why they are argued about so often.

An illustrative example

Take a small brownfield site in industrial use, being promoted for flats. The assessment values the land in its existing use by capitalising the rental income from the units on it. To that it adds a premium, justified by evidence of what similar owners in the area accepted when they sold.

The residual valuation then runs: gross development value of the flats, less construction costs, professional fees, finance, marketing, the levy, section 106 contributions, the biodiversity net gain obligation and the developer's return. Whatever remains is the residual land value.

If the residual comes out above the benchmark with full policy-compliant affordable housing, the scheme is viable and the argument ends. If it comes out below, the negotiation begins, and the council's reviewer will test the build cost allowance, the values assumed for the flats, and the premium, in that order. This example is illustrative, and every input would need site-specific evidence.

Some of those cost lines are worth understanding on their own, because they are routinely overstated. Off-site biodiversity obligations are priced in units, and the note on biodiversity units sets out how that calculation works. Nutrient mitigation in affected catchments is priced separately again, as the nutrient budget explainer describes.

Where it is commonly misunderstood

The first misunderstanding is that the price paid sets the benchmark. It does not. A developer who paid a price assuming no affordable housing has taken a commercial risk, and national guidance says plainly that the price paid is not a justification for non-compliance.

The second is that a viability assessment is a neutral calculation. It is a model built from assumptions, and small changes to sales values or build costs move the answer by a lot. Objectors reading one should look at the inputs rather than the conclusion.

The third is that the benchmark is fixed once agreed. Many permissions now carry a review mechanism in the section 106 agreement, requiring the viability position to be recalculated at a stated trigger, often part-way through construction or at a set date if work has not started. If values have risen, additional affordable housing or a payment becomes due.

A fourth, common among objectors, is that a viability case settles the planning merits. It does not. Viability is one material consideration, and a scheme that is unviable with policy compliance can still be refused on design, heritage or highway grounds.

Terms that sit close to it

Existing use value is the current lawful use value without the new permission. Alternative use value substitutes a different use that could actually be delivered. Market value is what the land would sell for in the open market, which will usually reflect hope value and is therefore not a safe benchmark on its own.

Residual land value is the output of the calculation rather than an input. Gross development value is the value of the completed scheme. Whether a site sits inside or outside a settlement boundary affects the existing use value, the alternative use value and the prospects for either, and the note on settlement boundaries explains how those lines are drawn and changed.

What to do if it applies to your site

If you are an objector or a parish councillor, ask the council for the viability assessment and the independent review. Both are normally published. Then read four things: the existing use value and how it was derived, the premium and the evidence behind it, the build cost per square metre and its source, and the sales values assumed. Those four inputs decide the answer.

If you are the applicant, commission the assessment from someone who will defend it, expect the council to instruct a reviewer at your cost, and assume a review mechanism will be sought in the agreement.

Either way, the document has to be written to a recognised methodology and read by someone who understands valuation. Browse the full set of report types to see where a viability assessment sits in an application pack, and enter your postcode on PlanScope to see what a site is likely to need.

This is general guidance, not legal advice, and it is not valuation advice. Viability assessments should be prepared and reviewed by suitably qualified professionals, so check the position with your local planning authority or a chartered surveyor before relying on any of this. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.