A Guide to Expert Planning Evidence from a Former Council Chief
A Planning Inquiry is a unique form of legal theatre.
The stage is set, the evidence is filed, and the stakes—commercially and personally—could not be higher. You, as counsel, are preparing to navigate a complex web of policy, case law, and subjective judgement.
And sitting beside you is your expert witness.
In my 25 years in planning, I have seen this one variable—the quality of the expert—determine the outcome of more appeals than any other.
We’ve all seen the expert who buries the Inspector in a 200-page Proof of Evidence, hoping to win by sheer volume. We’ve also seen the one who, despite a decent report, “wilts” under the first breath of cross-examination, their credibility evaporating.
An appeal is not won by the weight of the paper. It is won by the strength of the argument and the credibility of the expert.
When you’re in an Inquiry, you don’t just need a planner. You need a strategist. You need a specialist who can stand their ground. You need an expert who is, for lack of a better word, tenacious.
The “Silverback” Standard
There’s a reason my company is called Silverback Planning. The name was given to me by a barrister, who, after a particularly challenging case, referred to my “unwavering defence of what’s right.” It’s a reputation I’ve worked hard to earn, and it’s a standard I bring to every appeal.
This standard is built on a “dual-sided” career that gives me a unique perspective.
As a private consultant, I’ve been the expert witness. I’ve given evidence in the Courts. I’ve built the cases that have won permissions for “impossible” sites, from Green Belt developments to complex equine facilities.
But as a former Head of Planning and Chief Planning Officer, I’ve been on the other side. I’ve instructed KCs. I’ve defended the council’s position at appeal. I’ve trained the officers who write the refusal notices.
This “insider” experience means I know exactly what a barrister needs from their planning expert. You don’t need another report-writer. You need an expert who delivers a case that is concise, robust, and watertight. You need someone who can not only write the evidence but defend it.
Here are the three pillars of a winning, tenacious expert planning strategy.
1. The ‘Error of Law’: Find the Crack, Not Just the Merits
The most common mistake a planning expert makes is to simply re-argue the merits of the case.
They write a Proof that says, “The council said this was a bad design, but we think it’s a lovely design.” This approach is a coin-flip. It invites a purely subjective judgement from the Inspector, who is just as likely to agree with the council as they are with you.
A tenacious expert does not re-argue the merits. They find the council’s error.
An appeal is a legal and evidential test. My first action is a forensic review of the council’s decision, not from a design perspective, but from a legal one. I am looking for the “crack” in their case.
Did they misinterpret their own policy? It is astonishingly common for a refusal to quote a Local Plan policy that, when read in full, doesn’t actually support their reason.
Did they fail to apply a relevant NPPF clause? Did they ignore the “tilted balance”? Did they fail to give “great weight” to a material consideration like heritage or design quality?
Was their procedure flawed? Was the committee report misleading? Did they fail to account for a key piece of evidence that was submitted?
Is their “evidence” just opinion? Did the officer state something “will cause harm” without any data, precedent, or analysis to back it up?
Finding this error is the foundation of the entire appeal.
It elevates the argument from “our opinion versus yours” to “the council has failed to make their decision in accordance with their own policy and national guidance.” You are no longer asking the Inspector for a favour; you are giving them a non-discretionary, legal reason to grant the appeal.
2. The “Bulletproof” Proof of Evidence: The ‘Golden Thread’ of Logic
Once we’ve found the crack, the Proof of Evidence (PoE) is the tool we use to widen it.
A “volume” expert writes a PoE like a history lesson. It’s chronological, sprawling, and buries the key points on page 87. It forces you and the Inspector to hunt for the argument.
A “tenacious” expert writes a PoE like a legal argument. It is not an academic paper; it is an advocacy document. Its sole purpose is to provide the Inspector with the “golden thread” of logic they need to write their decision letter in your favour.
My structure for a “bulletproof” PoE is always the same:
Identify the Refusal Reasons: It starts by quoting the council’s refusal reasons, word for word. This is the “test” we have to pass.
Systematically Dismantle Each One: The report is structured to address each refusal reason in turn. Not in a narrative, but in a forensic, “Section 1, Reason 1” format.
Apply the Evidence: For each reason, I apply the evidence. This isn’t just policy; it’s precedent (what else have they approved?), site-specific data (shadow diagrams, traffic counts), and the “error of law” we already identified.
Conclude: The conclusion is not a summary; it’s a call to action. It states that because the refusal reasons have been systematically proven to be unfounded and contrary to policy, the Inspector must grant the appeal.
This “scaffolding of logic” makes your job as counsel infinitely easier. You don’t have to search for the argument. It’s handed to you, chapter and verse. It also makes the Inspector’s job easier—a critical, and often overlooked, strategic advantage.
3. The Cross-Examination Test: Credibility Under Fire
A perfect Proof of Evidence is useless if your expert “wilts” under cross-examination. This is the moment of truth. This is where “tenacity” is truly tested.
Tenacity under fire is not about being argumentative or aggressive. That is a fatal flaw that destroys credibility.
Tenacity is about being an unwavering, clear, and credible advocate for the evidence. It’s about building trust with the Inspector.
My experience at the dispatch box—both for and against councils—has taught me what this looks like in practice:
Absolute Command of the Evidence: When asked “Where in your report…?” I can turn to the page, paragraph, and line. Instantly. This shows command and builds confidence.
Answer Only the Question Asked: An expert’s job is not to evangelize. It’s to provide clear, direct answers. If the answer is “yes,” I say “yes.” I don’t add “Yes, but…” unless it’s critical.
Know the Limits: I will never stray outside my expertise. If counsel asks me about highways or structural engineering, the answer is: “That is a matter for the highways expert.” This protects my credibility and the integrity of the case.
Concede Minor Points Gracefully: A good expert knows which hills to die on. If the opposing KC makes a valid, minor point (e.g., about a typo in a drawing reference), I will concede it immediately. “I accept that correction.” This demonstrates I am reasonable and builds my credibility for when I don’t concede on the major points.
Stay Calm. Stay Professional: Cross-examination is designed to rattle. A tenacious expert remains calm, professional, and clear. They are a reliable source of information for the Inspector, not a partisan combatant.
This is the “Silverback” standard. It’s why I am endorsed by KCs and have a reputation for handling the most complex cases.
Your Case Deserves a Tenacious Expert
An appeal is not just another planning application. It is a rigorous legal and evidential test.
To win, you don’t just need a planner with a good report. You need an expert strategist who can find the legal weakness, an advocate who can build a bulletproof argument, and a credible witness who can defend that argument under fire.
My reputation is built on these high-stakes cases. When your case needs a tenacious expert, let’s talk.
About the Author
Mark Turner is a Chartered Town Planner (MRTPI) and the founder of Silverback Planning Solutions. With over 25 years of dual-sided experience—including as a former Head of Planning and Chief Planning Officer—he provides tenacious, expert planning consultancy for architects, developers, and barristers on complex cases. He is known for his “unwavering defence of what’s right” and his track record of winning permissions for “impossible” sites.
Are you counsel preparing for a complex appeal or Public Inquiry? Let’s discuss the case.
