Proofs of evidence and rebuttals at inquiry

A proof of evidence at a planning inquiry is a witness's written evidence, signed by that witness, on which they will be cross examined. It is not a second statement of case and it is not counsel's submission. Treat it as either and the witness spends the first hour of cross examination explaining why they are giving evidence about matters outside their expertise.

The Inquiries Procedure Rules set the timetable, the summary requirement and the exchange. Everything else, including whether a rebuttal is accepted, is managed by the inspector.

What a proof of evidence is

The proof sets out what the witness says about the matters in dispute within their field, the evidence they rely on, and their conclusion. It is their evidence in chief, so the witness is normally taken through only the summary at the inquiry rather than reading the whole document.

Three features distinguish a strong proof. The witness speaks in the first person about what they have done and what they conclude. Every material assertion is either sourced to a document in the core documents list or identified as the witness's own professional judgement. And the scope stays within the discipline: a planning witness does not opine on acoustics, and an acoustician does not conclude on the planning balance.

The last one is where proofs most often go wrong. A transport witness who concludes that the appeal should be allowed has stepped outside their evidence, and opposing counsel will use it.

Where a witness disagrees with something in their own client's earlier submission, say so in the proof. Discovering it in cross examination is worse.

Summary proofs and length conventions

The Rules require a written summary where a proof of evidence exceeds 1,500 words, and the summary is the document read at the inquiry. That number sets a practical convention: proofs run long, summaries are the working document.

A good summary is not an abstract. It follows the structure of the proof, carries the conclusions in the same order, and can be read aloud in fifteen to twenty minutes. Anything longer loses the room, including the inspector.

On length of the proof itself, the discipline is to write what the issues require. A proof covering three main issues in a housing appeal might run to forty pages; a highways proof dealing with one junction might be twelve. Padding is visible, and an inspector who has read six proofs in a week notices which ones repeat the statement of case.

Appendices are not part of the word count, which invites a tactic that does not work: moving argument into an appendix. Inspectors read appendices as evidence, not as argument, and material argument hidden there tends to be ignored.

Exchange dates and the timetable

The timetable runs from the start date set by the Planning Inspectorate. Statements of case come first, then the statement of common ground, then proofs of evidence, which under the Rules are due no later than four weeks before the inquiry opens.

Exchange is simultaneous. Neither party sees the other's proofs before sending their own, which is the whole reason the rebuttal question arises.

Practical consequences follow from the four week point. The witness has to be substantively finished about six weeks out, because the proof needs review, the core documents need assembling and the appendices need paginating. Instructing an expert three weeks before the deadline produces a proof written at speed, and speed shows under cross examination.

The statement of common ground deserves more attention than it usually gets. Every fact agreed there is a fact that cannot be attacked, and a well negotiated statement can remove an entire strand of the other side's case before any proof is written.

When a rebuttal is permitted

Rebuttal proofs are not provided for in the Rules. They exist by permission, and the Inspectorate's procedural guidance treats them as the exception rather than the norm.

The inspector will normally allow a rebuttal where the other side's proof raises something new: a survey not previously disclosed, a methodology not foreshadowed in the statement of case, a policy point that emerged after the statements were exchanged. The deadline is set by the inspector, often around a week before the inquiry.

What will not be allowed is a rebuttal that restates the main proof with added emphasis, or that deals with points the party knew about and chose not to address. Submitting one anyway irritates the inspector, wastes a week of the witness's time, and can attract a costs application for unreasonable behaviour.

So the test before drafting is simple. Could this point have been made in the main proof? If yes, it belongs in cross examination, not in a rebuttal.

Scope limits on rebuttal evidence

Where a rebuttal is permitted, keep it to the new material and say at the outset what that material is. A short opening paragraph identifying the paragraphs of the opposing proof being answered makes the document usable and demonstrates the discipline the inspector asked for.

Do not introduce new positive evidence in a rebuttal. A rebuttal that contains the appellant's first analysis of viability, or the authority's first traffic count, invites an application to exclude it, and the inspector may allow an adjournment at the objecting party's cost.

Keep it short. A rebuttal running to the length of the original proof is not a rebuttal.

And check whether a rebuttal is needed at all. Where a point can be dealt with in cross examination by the party's advocate, that is usually more effective than a written answer the other side has a week to prepare for.

Appendices and core documents

The core documents list is the shared bundle of policy, guidance, appeal decisions and application material that both parties refer to. Agreeing it early saves inquiry time and prevents the situation where two witnesses cite different versions of the same document.

Two conventions are worth holding to. Anything cited in a proof should be in the core documents or in that witness's appendices, with a reference the inspector can follow. And where a party relies on an appeal decision, include the decision letter rather than a summary of it, and be clear that it is indicative of how inspectors have approached an issue rather than binding precedent.

Appendices should be paginated continuously and indexed. It sounds trivial. In a three day inquiry where the inspector is following four witnesses across two bundles, a clean reference system materially changes how easy your case is to follow.

Where national policy shifts between exchange and the inquiry, both parties will usually be invited to make further representations, which is the situation set out in when national policy changes during your appeal.

Preparing a witness for cross examination

The most common failure at inquiry is not weak evidence. It is a witness defending a position they do not actually hold because they feel they must defend the proof.

Preparation that helps: a session identifying the three or four propositions in the proof that are most exposed, and agreeing in advance what the witness will concede. Conceding a fair point cleanly costs little and buys credibility for the points that matter. Defending an indefensible one costs the whole proof.

Other points that repay attention. The witness should know their own appendices well enough to find a figure without hunting. They should be clear about what is fact, what is professional judgement, and what is assumption, and be able to say which is which when asked. And they should answer the question that was asked, briefly, then stop.

For a party whose case rests on a policy assessment, the discipline established in a well-drafted Planning Statement at application stage carries straight through: identify the development plan policies, apply them, and reach a conclusion the witness can defend. Where the refusal turned on a subject-specific issue, such as the loss of an employment site, the technical witness carries that ground and the planning witness carries the balance. Third parties may also appear and give evidence, and their role is described in how neighbours take part in a planning appeal.

A last practical note. Inquiries are recorded in the inspector's notes rather than by transcript, so what the inspector writes down is what survives. Short, clear answers get recorded accurately. Long ones get summarised, and the summary is not yours.

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.

Browse the PlanScope report types to see which supporting evidence an appeal case is likely to draw on.