When an inspector reopens viability at appeal

Viability at appeal is won on three or four numbers, and one of them is almost always benchmark land value. An inspector reopens viability when the council's reason for refusal turns on affordable housing or obligations and the appellant says the policy package cannot be afforded. From that moment the appeal becomes an evidential exercise about inputs, and the party whose inputs are better sourced tends to win.

Inspectors are not valuers. They are experienced at spotting an input that has been chosen rather than derived.

The policy starting point

National policy expects viability to be tested at plan making, so that adopted policy requirements are already deliverable across the plan area. Planning Practice Guidance follows through: a viability assessment at application stage should only be necessary where particular circumstances justify it, and the applicant has to demonstrate those circumstances.

That framing matters at appeal because it puts the burden where it sits. The appellant has to explain why this site is different from the sites the plan assumed. Abnormal ground conditions, a heritage asset with a repair liability, a severely constrained access, an existing use with a value the plan did not anticipate: these are the arguments that work. A general assertion that build costs have risen is not, because the plan viability evidence has its own indexation.

The Planning Practice Guidance is equally direct on land price. The price paid for land is not a justification for failing to comply with policy requirements. Inspectors quote that sentence often.

When viability becomes a main issue at appeal

It becomes a main issue in three situations. The refusal cites a failure to provide policy compliant affordable housing and the appellant relies on viability. The council and the appellant agree the principle of development but disagree about the obligations package. Or the appellant appeals a refusal on other grounds and the council adds an obligations reason, which happens more often than it should.

Procedure choice follows from that. A viability dispute with two expert valuers is hard to run by written representations, because the inspector cannot test the inputs. Hearings work for a narrow dispute on one or two inputs. An inquiry is the right forum where benchmark land value, build costs and profit are all contested, and where cross examination will do real work.

Decide procedure early and say why in the appeal form. An inspector who reads a written representations appeal containing two irreconcilable appraisals will often convert it, and the conversion costs weeks.

Disclosure and the presumption of transparency

The Guidance is clear that viability assessments should be publicly available, in an accessible form, with an executive summary. Redaction is limited to commercially sensitive material, and the reasons for any redaction have to be given.

Appellants underestimate how badly a redaction fight goes. A council that cannot see the inputs cannot agree them, the inspector cannot test them, and the practical result is that the assessment carries less weight. If a land transaction cannot be disclosed at all, consider whether the case can be run without relying on it rather than redacting the document that supports it.

Put the appraisal in as a working file where the inspector's directions allow it, with the formulae intact. A locked PDF of an appraisal invites the council's expert to rebuild it, and rebuilt appraisals surface every assumption you hoped would pass unnoticed.

The statement of common ground on inputs

This is where most of the value lies. Agree what you can, line by line, and leave the inspector with a short list of genuine disputes.

A statement of common ground that agrees the first column and sets out each side's figure in the second column is worth more than a two hundred page appraisal. It also protects you on costs, because it shows the issues were narrowed properly.

Benchmark land value and why it dominates

The Guidance sets benchmark land value on an existing use value plus a premium basis, with the premium reflecting a reasonable return to a willing landowner, and with the policy requirements and levy liability taken into account. Alternative use value is only relevant where there is an existing implementable permission for that alternative.

Disputes cluster in two places. The existing use value itself, where the parties disagree about the income the current use generates or about whether a use is still continuing in fact. And the premium, where there is no fixed percentage and the arguments run on comparables, on landowner behaviour in the local market and on what the plan viability evidence assumed.

Illustrative example: a former builder's yard with a short unexpired lease. The appellant valued the existing use on the passing rent capitalised at a yield drawn from recent local transactions, and applied a premium at the upper end. The council took the same rent but argued the yield reflected hope value rather than the existing use, and applied a lower premium. The gap between the two benchmark figures was larger than the entire disputed affordable housing contribution, which is a common pattern and a reason to resolve the benchmark first.

Where the scheme involves the loss of a vacant building, the credit position is its own argument and we cover it in vacant building credit and why councils resist it.

The council's rebuttal and its expert

Councils instruct external valuers for appeal viability, and the instruction is usually narrow: review the appellant's appraisal and report on the inputs. That produces a rebuttal rather than a competing appraisal, which is tactically useful to the council because it only has to show that the appellant's figures are unreliable.

Answer it on its own terms. Take each criticised input, state the source, state the date, and state what the figure would be on the council's method. Where the council's expert is right about something, concede it and show the sensitivity. Conceding a build cost point and demonstrating that the conclusion survives is far stronger than defending every number.

Both sides' authors should be working to the RICS professional statement on financial viability in planning, which requires objectivity regardless of who instructs. Councils generally expect a suitably qualified author, and professional review of any draft is strongly advised. If the appellant's appraisal was prepared by someone without valuation credentials, expect that to be raised.

Costs risk on a weak viability case

Costs awards follow unreasonable behaviour that causes wasted expense. A viability case that is advanced and then abandoned at the inquiry, an assessment that withholds inputs until the last minute, or a refusal reason on obligations that the council cannot evidence: all three have drawn costs applications.

So test the case before you run it. If the viability position depends on a single contested input, and losing that input loses the appeal, consider offering a review mechanism instead. A late stage review clause in the agreement gives the council its upside if values improve and gives the scheme its consent now, and the mechanics are set out in overage clauses and review mechanisms in a section 106. The interaction with the policy requirement itself is covered in the Affordable Housing Statement, and the underlying document is the Viability Assessment.

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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