Confidentiality and publication of viability evidence

The default position on viability assessment publication is that the whole thing goes on the planning register for anyone to read. National planning guidance is explicit that assessments submitted in support of an application should be publicly available, and that inputs and findings should be set out in a way that is accessible to a non-technical audience. Redaction is the exception, it has to be justified, and the categories that survive scrutiny are narrower than most developers expect.

Assume publication when you commission the appraisal. That single assumption changes how it is written.

Why the presumption exists

Viability arguments reduce affordable housing and infrastructure contributions that adopted policy would otherwise require. Where a public benefit is being given up, the reasoning behind it is a matter of legitimate public interest, and the shift towards openness in national guidance followed years of assessments being withheld and decisions being taken on evidence nobody outside the room had seen.

The guidance also standardises the inputs, which supports openness. Benchmark land value based on existing use value plus a premium, a defined approach to developer return, and transparency about assumptions all make an assessment comparable with others rather than a bespoke document requiring interpretation.

For applicants this cuts both ways. An assessment that is written to be read will be tested by third parties, but it is also far harder for the council's assessor to dismiss.

What can reasonably be redacted

Very little, and the argument has to be specific.

The categories that occasionally succeed are personal data about individuals, which must be removed in any event under data protection law, and narrowly commercial terms that are not part of the viability argument. A land option agreement's break clauses, a contractor's rates from a live competitive tender, or the terms of a funding facility can sometimes be withheld where the numbers derived from them are still disclosed.

The categories that fail are the ones people usually try. The purchase price paid for the site. The developer's target profit. Build cost totals. Sales values and the comparable evidence behind them. Each of these is a load-bearing input, and withholding it removes the ability of anyone to check the conclusion.

A blanket claim over an entire appraisal will not survive a request. Nor will an argument that publication would embarrass the applicant or affect a future negotiation, because commercial disadvantage in the abstract is not the same as identified harm.

Information access law and how it bites

Planning information is environmental information, so requests are handled under the Environmental Information Regulations 2004 rather than the Freedom of Information Act in most cases. That matters, because the regulations are less generous to the holder of the information.

Regulation 12(5)(e) allows confidentiality of commercial or industrial information to be protected where confidentiality is provided by law to protect a legitimate economic interest. Every element of that has to be made out, and the exception is then subject to a public interest test with an express presumption in favour of disclosure.

The practical consequence is that a council receiving a request will consult the applicant, weigh the arguments and, more often than not, disclose. An applicant who has marked a document confidential without explaining why has given the council nothing to work with.

Where a decision goes against you, the appeal route runs to the Information Commissioner and then to the First-tier Tribunal, which takes months and generates its own publicity.

How councils handle third party assessments

Councils appoint their own assessor to review the applicant's appraisal, and the review is normally published alongside it. The review will restate the applicant's inputs, so material redacted from the original often reappears in the assessor's analysis.

That is worth thinking about before you negotiate a redaction. A figure removed from your document and quoted in the council's review has been published anyway, and the redaction has bought nothing but the appearance of secrecy.

Some authorities publish a viability protocol setting out what they will disclose and when. Where one exists, read it before submitting, because it will tell you the authority's settled position and save an argument.

Timing is the other variable. Some councils publish on receipt, others hold the assessment until the officer report is written, and a few publish only the review. None of those approaches removes the obligation to disclose on request, so the difference is one of convenience rather than protection. Ask the case officer at the pre-application meeting what the authority's practice is, and record the answer.

Writing an appraisal you are content to publish

The practical response is to write two documents rather than one.

The first is the appraisal itself, with the inputs, the sources for each of them, the sensitivity analysis and the conclusion. Structure it so that a reader can follow the argument from existing use value to the residual, and cite the source for every value, because an unsourced number reads as an invented one.

The second is a short non-technical summary, written for a councillor or a resident, stating what the policy requirement is, what the scheme can support, why, and what the review mechanism will do about it if things improve. Councils increasingly ask for this, and where they do not, providing it anyway shapes how the case is understood.

• Keep personal data out of the main document entirely
• Put anything truly sensitive in a clearly identified appendix with a written justification, so a redaction decision can be taken on that appendix alone
• Use ranges where a precise figure is commercially live and the range still supports the conclusion
• Avoid internal commentary about negotiating positions; write as if the case officer, the local newspaper and an objector's surveyor will all read it, because they may

A Viability Assessment prepared on that basis is also easier for the council's assessor to review quickly, which shortens the determination period.

Where the argument usually goes wrong

Three failure modes recur.

Submitting a full appraisal marked confidential, with no schedule of what is claimed and why, which forces the council to make the argument for you and produces a disclosure decision you did not shape.

Redacting inconsistently across the appraisal, the Affordable Housing Statement and the covering letter, so that the withheld figure appears in one of them.

Relying on a confidentiality agreement with the council. A public authority cannot contract out of its statutory obligations, and an agreement of that kind does not bind it when a request arrives.

There is one honest uncertainty worth stating. The line between a legitimate economic interest and ordinary commercial preference is not sharply drawn, and different authorities and different Information Commissioner decisions have landed in different places on similar facts. Take advice on the specific document rather than relying on what happened on another scheme.

Write the appraisal for publication, keep the sensitive material in one identified appendix, and provide the plain-language summary yourself. Browse the report types that a major application needs, or enter your postcode to see the constraints on a site.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.

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