Independent audit of a technical report and who pays
An independent audit is commissioned by the authority, carried out by its appointed consultant and paid for by you. Here is how the process and the costs work.
An independent audit is a technical review commissioned by the local planning authority, carried out by a consultant the authority appoints, and paid for by the applicant. It is a different thing from a peer review, which you commission yourself to test your own evidence before anyone else sees it. Audits appear where a local plan policy or a supplementary planning document provides for one, and basement impact assessments in some London boroughs are the best known example.
Budget for the fee, for at least one round of responses, and for the programme. Audits add weeks, and an audit comment that your consultant has to model again adds more.
Where audit regimes apply
Audit regimes are a local policy choice rather than a national requirement, so the starting point is the development plan and any supporting document for the topic.
The pattern is consistent where they exist. The policy identifies a category of technical evidence that the authority does not have in-house capacity to check, sets out that an independent review will be commissioned, and states that the applicant meets the cost. Basement and subterranean development policies are the clearest case, because the engineering issues of ground movement, hydrogeology and structural stability sit well outside a planning officer's expertise and the consequences of getting them wrong land on neighbours.
Other topics attract a similar approach even without a named audit regime. Viability evidence is routinely reviewed by a consultant the authority instructs, as the Planning Practice Guidance on viability anticipates. Transport modelling is reviewed by the highway authority, sometimes using an external consultant. Daylight and sunlight evidence on contested urban schemes, air quality dispersion modelling and acoustic modelling are all reviewed externally from time to time.
Read the policy and the validation list before you submit. If an audit applies, the process starts whether you have budgeted for it or not.
Who appoints the auditor and what that changes
The authority appoints. That matters in three ways.
The auditor's duty is to the authority, not to you, so the output is advice to the decision-maker rather than a negotiated position. You will usually not choose the auditor, and you may not know who it is until the first comments arrive. And the auditor has no obligation to find your evidence acceptable, only to say whether it meets the standard the policy requires.
Some authorities operate a panel of pre-approved auditors and will tell you who is on it. Asking at pre-application stage is worth doing, because a panel member who has reviewed similar schemes will probe predictable things, and your consultant can address them in the first submission rather than the third.
The auditor's independence also means you should not approach them directly. Route everything through the case officer.
How the cost is recovered
Local authorities can charge for discretionary services, and section 93 of the Local Government Act 2003 is the usual power relied on. In practice the recovery happens by one of three routes.
| Route | How it works | What to watch |
|---|---|---|
| Fee paid up front | A published audit fee paid before the review starts | Whether it covers one round or all rounds |
| Planning performance agreement | Audit cost built into a PPA alongside officer time | Timescales become contractual, so negotiate them |
| Section 106 or undertaking | Applicant undertakes to meet reasonable audit costs | Define "reasonable" and cap it |
The first is simplest and the third is the one that produces disputes. Where you are asked to meet costs without a stated figure, ask for an estimate, a scope, an hourly rate and a cap in writing before agreeing. Audits that run to three rounds on an uncapped basis are how a modest review fee turns into a serious number.
Where a published schedule exists, those figures are indexed or reviewed periodically, so check the current schedule rather than reusing a figure from a previous application.
Audit against peer review
The two are often confused, and the difference affects both cost and strategy.
A peer review is yours. You instruct it, you own the output, and you can act on it or not. It is privileged in the practical sense that nobody else sees it unless you choose to submit it. Its purpose is to find the weaknesses before the authority does. The article on peer review and second opinions on technical evidence sets out how to scope one.
An audit is the authority's. The output goes on the public file, objectors read it, and an adverse audit comment becomes a material consideration you have to answer.
The practical consequence is that on any scheme facing an audit, a peer review first is money well spent. It costs a fraction of the delay caused by an audit round that finds a methodological problem your own consultant could have caught.
Scope, and responding to comments
An audit is scoped to the policy requirement. A basement audit typically covers the adequacy of the ground investigation, the hydrogeological conceptual model, the structural and ground movement assessment, the predicted damage category for neighbouring buildings, the monitoring proposals and the construction method assumptions. A Basement Impact Assessment that addresses each of those heads explicitly is easier to audit than one organised around a different structure.
When comments arrive, resist the urge to argue the first draft.
- Separate the comments into factual corrections, requests for information, methodological challenges and matters of judgement.
- Answer the factual and information points immediately and completely, because they are the quickest to close.
- Have your consultant respond to methodological challenges in a technical note with references to the standard relied on.
- On matters of judgement, say where you disagree and why, and say what you have changed.
- Submit one consolidated response rather than a stream of emails.
A consolidated response usually closes an audit in one further round. A piecemeal response invites a second full review.
Where the audit is wrong
It happens. Auditors apply the wrong standard, misread a drawing, or import a requirement the policy does not contain.
The escalation route is through the case officer, not around them. Put the disagreement in writing, identify the specific comment, state the standard or policy you say applies, and ask for the point to be referred back to the auditor. Where it remains unresolved, you are entitled to have your position reported to the decision-maker alongside the audit, and the committee report should record both.
An audit is advice. The decision is the authority's, and an unresolved technical dispute can be tested at appeal, where both the auditor's view and your consultant's view are evidence rather than determination. Keep the audit correspondence organised for that reason. Where different parties have drafted and submitted the evidence, the position on responsibility needs settling early, and the piece on liability when one party writes and another submits covers the ground.
Budgeting for the process
Allow for five items rather than one: the audit fee, your consultant's response time, any additional site investigation or modelling the audit requires, the programme extension, and the cost of a peer review in advance.
The programme is the item that hurts most. An audit round can add six to eight weeks to a determination even where the evidence is accepted, so expect an extension of time and build it into any option agreement or funding deadline. Where a scheme depends on a fixed date, the audit should be commissioned at pre-application stage if the authority will agree to that, rather than after validation.
If you want a specialist to review your evidence before it goes in, the PlanScope professional directory is the route for a review request and sign-off.
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. For specialist technical reports, qualified professional input may be required.
Frequently asked questions
What is the difference between an audit and a peer review?
An audit is commissioned by the local planning authority, carried out by a consultant it appoints, and the output goes on the public file as advice to the decision-maker. A peer review is commissioned by you, the output is yours, and its purpose is to find weaknesses in your evidence before anyone else does.
Can the council make me pay for the audit?
Where a local plan policy or supplementary planning document provides for independent audit, yes. Authorities can charge for discretionary services, and section 93 of the Local Government Act 2003 is the power usually relied on. Recovery happens through a published fee, a planning performance agreement or an undertaking to meet reasonable costs.
How long does an audit add to the determination?
Plan for six to eight weeks for a single round even where the evidence is accepted, and longer where additional investigation or modelling is required. Expect to agree an extension of time. Where a scheme depends on a fixed funding or option date, ask whether the audit can be commissioned at pre-application stage instead.
What if I think the auditor is wrong?
Put the disagreement in writing through the case officer, identifying the specific comment and the standard or policy you say applies, and ask for it to be referred back. An audit is advice, not a determination. If it remains unresolved, your position should be reported to the decision-maker alongside the audit and can be tested at appeal.
Should I get a peer review before submitting?
On any scheme facing an audit, usually yes. A peer review costs a fraction of the delay caused by an audit round that finds a methodological problem, and because you own the output you can fix the evidence before it reaches the public file. Scope it to the same heads the audit will cover.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.