When to commission an independent peer review

Commission an independent peer review when the decision turns on a technical document you cannot test yourself, and when the cost of being wrong is larger than the review fee. On most applications that never happens. On a viability case, a contested basement impact assessment, a nutrient budget or an appeal where the council has produced its own expert evidence, an independent peer review of a planning report earns its fee several times over.

Situations where a review pays for itself

Four patterns come up repeatedly.

The first is where the council has commissioned its own review of your evidence, which is standard practice on viability assessments and on basement impact assessments in several London boroughs. You are then in a technical argument between two experts, and having your own reviewer read both documents before you respond changes the quality of that response.

The second is where you have inherited a report. A site bought with a planning permission, a scheme taken over from another team, a survey commissioned by a former owner. You did not choose the author and you do not know the assumptions. Reviewing a specialist report you did not commission covers the mechanics of that first read.

The third is appeal. Evidence that will be tested in cross-examination at an inquiry deserves to be tested privately first, by someone who is paid to find the weakness rather than to defend it.

The fourth is where a consultee objection rests on a methodology you suspect is wrong. That is a narrow, expensive argument to have, and you should only have it with a reviewer who has run the method themselves.

Scoping a review so it is actually useful

An unscoped review produces a list of everything the reviewer would have done differently, which is not the same as a list of things that matter.

Write the brief around decisions. State the question the report is being used to answer, the objections that have been raised, and what you intend to do with the review. Then ask for three specific outputs: whether the methodology follows the recognised standard, whether the input assumptions are supportable, and whether the conclusion follows from the analysis.

Ask for the review to distinguish between errors, matters of professional judgement and matters of presentation. Those three categories lead to different actions, and a review that blends them is hard to use.

Set a page limit. A four-page review that names five issues is more useful than a thirty-page commentary.

Choosing a reviewer without a conflict

Independence is the whole point, so screen for it properly. A reviewer who has worked for the applicant's competitor on the same site, who has advised the council on the relevant policy, or who is in the same practice as the original author is not independent, whatever they say.

Ask three questions in writing before instruction. Have you advised any party with an interest in this site or this application. Do you have a current or recent commercial relationship with the original author's practice. Would you be content for this declaration to be submitted with the review.

The third question is the useful one. A reviewer willing to have their declaration read by the council is a reviewer whose opinion will carry weight. The wider issue is covered in independence and conflicts of interest in planning evidence.

Competence matters as much as independence. A reviewer should hold the same qualification as the original author and, ideally, more experience of the specific method.

How to present review findings

This is where reviews are wasted. A peer review is an internal working document by default, and you decide whether it becomes part of the submission.

The general rule is to submit the corrected document rather than the critique. A council reading a peer review of your own consultant's work will reasonably ask why the original was not right in the first place.

Where the review is submitted, it needs the reviewer's name, qualifications, the declaration of independence and a clear statement of the scope. An anonymous critique carries no weight at all.

Where a review weakens your case

Be honest about this before you commission. A review is a document, and documents can be disclosed.

If the review finds that your evidence is wrong, you now know that, and proceeding without fixing it is a much worse position than not having asked. At an inquiry, an expert who has been shown a review identifying a flaw and has not addressed it is in serious difficulty under cross-examination.

There is also a professional dimension. Commissioning a review of your own consultant's work without telling them is corrosive, and it usually comes out. Tell them, and invite them to respond to the findings. Most competent consultants welcome it.

So the decision to review is a decision to act on what it finds. If you are not prepared to do that, do not commission it.

Cost, programme and the appeal timetable

Reviews are small commissions by planning standards, usually a matter of days rather than weeks of work, but the programme risk sits in the response rather than the review itself.

1. Allow time for the reviewer to request the underlying data, which is often the slow step.
2. Allow time for the original author to respond to the findings.
3. Allow time to re-issue the corrected document and for the council to reconsult.
4. At appeal, work backwards from the statement of case and proof of evidence deadlines rather than from the inquiry date.

Commissioning a review two weeks before a proof of evidence is due is a way of paying for anxiety rather than for evidence.

Using a review at appeal

At an inquiry, the reviewer may appear as a witness in their own right, or the findings may be absorbed into the main expert's proof. The second is more common and usually more effective, because it keeps the number of witnesses down.

If the reviewer does give evidence, remember that an expert's duty is to give an independent opinion to the decision maker, not to advocate for the party paying them. A reviewer who writes like an advocate damages the case they were hired to support.

Where the dispute is about whether the council behaved reasonably in requiring or rejecting evidence, a review can also support an application for costs. That is a separate argument with its own tests, and it should be made on the published costs guidance rather than on a sense of grievance.

The professional directory on PlanScope is one route to a reviewer who can check and sign off a draft, and the same independence and competence questions apply.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.