Council viability evidence: what officers publish and redact

National guidance is unambiguous on viability transparency: viability assessments should be prepared on the basis that they will be made publicly available, other than in exceptional circumstances, and even where an exception is justified an executive summary should still appear. Councils apply that by placing the appraisal on the planning register with the rest of the application documents, and the viability assessment council transparency question is now about what, if anything, can be redacted rather than whether the document appears at all.

Plan for publication from the first spreadsheet. An appraisal written on the assumption that nobody outside the council will read it produces the assumptions that get quoted back at committee.

The presumption that appraisals are published

The starting position is that the whole assessment, including inputs, is published. Officers will normally publish the appraisal, the applicant's covering report and their own independent reviewer's report.

Redaction is possible where information is commercially sensitive in a real sense, and the bar is higher than most applicants expect. A purchase price already registered at the Land Registry is not confidential. Build cost rates drawn from a published cost index are not confidential. A specific negotiated contractor rate or a named funding arrangement may be.

Where redaction is sought, ask for it explicitly with reasons for each item, and provide an unredacted version to the council and its reviewer. Blanket claims over an entire document are usually refused, and the refusal arrives late.

Freedom of information requests are the other route in. Objectors and neighbouring landowners use them, and information already published cannot be withheld from them afterwards.

Benchmark land value and existing use value

The benchmark land value is where most disputes start. National guidance sets the approach as existing use value plus a premium to the landowner, with the premium reflecting a reasonable incentive to bring the land forward while allowing for policy requirements including affordable housing.

Three points cause argument. Existing use value must reflect the current use, not a hoped-for use. The premium must be justified by evidence rather than asserted as a percentage. And a price actually paid for the land is not the benchmark, because a price that assumed no affordable housing cannot be used to argue that affordable housing is unviable.

Alternative use value can be a cross-check where the alternative has planning permission or would clearly be permitted. Speculative alternatives carry little weight.

Where a scheme sits on land in the applicant's ownership for decades, the existing use value calculation still applies. Sentimental or historic figures have no place in the appraisal.

What councils accept as evidence

Costs and values both need sourcing, and each has an accepted hierarchy.

National guidance indicates that a return of 15 to 20 per cent of gross development value may be considered a suitable return to developers for market housing, with a lower figure appropriate for the affordable element. Departing from that range needs an explanation tied to risk on that specific site.

Abnormal costs attract the most scrutiny. A remediation allowance of a stated sum per square metre with no site investigation behind it will be discounted by the reviewer, and the discount usually exceeds what an investigation would have cost.

A Viability Assessment prepared to the relevant professional standard is expected to be objective rather than advocacy, and the standard imposes duties on the author about independence and reporting. Councils usually expect a suitably qualified author, and professional review is strongly advised.

Review mechanisms in the section 106

Where a scheme is permitted with less than policy-compliant affordable housing, the council will normally require review mechanisms in the legal agreement.

An early stage review triggers where implementation is delayed beyond an agreed period, testing whether values have moved. A late stage review triggers at a defined point of sales or practical completion, capturing any uplift and converting a share of it into additional affordable housing or a payment.

Some authorities also apply a mid stage review on larger phased schemes. Greater London authorities operate a structured approach with a faster route for schemes meeting a policy threshold without review, which is worth checking against your own numbers before deciding how much affordable housing to offer.

Negotiate the mechanics carefully. The definition of costs and values at review, the treatment of finance, the cap on additional contribution and the timing all matter more than the headline percentage. A poorly drafted late stage review can capture ordinary inflation as if it were profit.

Independent assessment and its cost

Councils almost always appoint their own reviewer, and the applicant pays. That is arranged either through a fee agreed at validation or through a clause in a planning performance agreement.

Budget for it, and engage with it. The reviewer's questions are the questions the officer will rely on, and answering them properly in writing is faster than arguing at committee. Where the reviewer's assumptions differ from yours, ask for their inputs and reconcile line by line in a table showing both positions and the difference.

Where agreement is impossible, the officer's report will present both figures. A clear reconciliation table gives members something to decide from. A dispute conducted through adjectives gives them nothing.

Where the argument usually lands

Officers rarely reject a viability case outright. What happens instead is a narrowing: the reviewer accepts the build costs, disputes the sales values by five per cent, adjusts the benchmark land value, and the resulting residual supports more affordable housing than the applicant offered.

Anticipate that. Run your own appraisal at the reviewer's likely assumptions before you submit, and decide in advance what you would accept. An applicant who arrives at that meeting with a prepared position secures a decision. One who has to take the numbers away and rebuild the model loses a committee cycle.

But do not offer a shortfall you cannot defend. A scheme that could deliver policy-compliant affordable housing and argues otherwise invites a refusal that an inspector will uphold.

Preparing an appraisal that survives scrutiny

Write it as though a hostile but competent reader will check every line, because one will.

State every assumption with its source. Show the residual calculation as well as its output. Provide a sensitivity analysis on the two or three inputs that actually move the answer, usually sales value, build cost and finance. Include the model itself in a live format so the reviewer can interrogate it rather than rebuilding it.

And keep the Affordable Housing Statement consistent with the appraisal. A statement offering a tenure split that the appraisal never tested is the contradiction reviewers find first.

For the narrative that ties the viability case to policy, a Planning Statement should set out the policy requirement, the offer, the reason for any shortfall and the review mechanism proposed, in that order.

To scope the documents a major application needs, browse the report types by category.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.

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