A medico-legal report is worth exactly what its independence is worth. A solicitor instructing an expert is not buying support for a case. They are buying an opinion that will still stand up when the other side reads it, when it is tested in a joint statement under CPR 35.12, and when it is put to the expert in cross-examination.
In short: an independent clinical opinion is one reached on the evidence and the reasoning alone, which would read the same whichever party had sent the instructions. CPR Part 35 makes the expert’s duty to the court override the duty to whoever instructs and pays them. Independence is not a professional courtesy. It is the condition on which expert evidence is admitted at all.
Prof. Sandip Hindocha is a consultant plastic surgeon preparing CPR Part 35 reports for instructing solicitors. What follows sets out how independence is defined in the rules, where it comes under pressure, and how it can be assessed before an expert is appointed.
What independence actually means in an expert report
Independence is often treated as a tone of voice, something an expert achieves by writing carefully and avoiding strong language. It is not. It is a property of how the opinion was reached, and a measured tone sits perfectly comfortably on top of a partisan conclusion.
The working test is simple. An opinion is independent when the reasoning would be identical had the instructions arrived from the opposing party. The expert reads the records, applies the relevant professional standard, and reaches the conclusion the evidence supports. The identity of the instructing party changes the address on the letter and nothing else.
That is easy to state and harder to apply, because most of what threatens independence is neither conscious nor dishonest. An expert who has read a well argued letter of instruction has already been handed a frame. The rules exist because that pressure is the ordinary condition of litigation rather than an unusual event.
The rule that puts the court first
The governing provision is short. CPR 35.3 states that it is the duty of experts to help the court on matters within their expertise, and that this duty overrides any obligation to the person from whom experts have received instructions or by whom they are paid.
Practice Direction 35 makes the same point in terms of the product rather than the person. Paragraph 2.1 requires that expert evidence should be the independent product of the expert, uninfluenced by the pressures of litigation. Paragraph 2.2 requires objective and unbiased opinion and says the expert should not assume the role of advocate. Paragraph 2.3 requires the expert to consider all material facts, including those which might detract from the opinion, and paragraph 2.5 requires any material change of view to be communicated.
Paragraph 2.3 does the most work in practice and is the one most often quietly skipped. A report that only ever finds support for the instructing party’s position is not independent, however carefully it is written. CPR 35.10 closes the loop by requiring every report to end with a statement that the expert understands and has complied with that duty, which is the hook on which a cross-examination about partisanship will be hung.
Where the pressure to lean comes from
Three pressures account for most of the drift, and they apply equally to experts instructed by claimants and by defendants.
Pressure from the instructing party
Letters of instruction are written by advocates, and a good one sets out the case theory clearly enough that an expert absorbs it before reaching the records. The counter is procedural rather than temperamental. Read the primary records first where the sequence allows, form a provisional view on the clinical material alone, then read the instructions to see what is actually being asked.
Pressure from repeat instruction
An expert who works predominantly for one firm, or for one side of the litigation, is exposed to a pull that operates without anyone intending it, because unhelpful reports get noticed. That is a reason to keep a balanced instruction base, and it is the pressure most likely to be raised in cross-examination.
The pull of a coherent narrative
The most powerful pressure is intellectual. Once an expert has formed a view that explains the evidence neatly, later material that complicates it is easy to discount. The only reliable defence is the discipline paragraph 2.3 describes, which is to go looking for the material that cuts against the conclusion and to deal with it in the report rather than around it.
The Ikarian Reefer duties and why they still set the standard
The modern statement of what expert evidence should be predates the Civil Procedure Rules. In National Justice Compania Naviera SA v Prudential Assurance Co Ltd, known as The Ikarian Reefer, [1993] 2 Lloyd’s Rep 68, Cresswell J set out a list of duties that has been cited ever since and that fed directly into Part 35.
In summary, the evidence should be the independent product of the expert and uninfluenced by the exigencies of litigation. The expert should give objective and unbiased assistance within their expertise and never assume the role of advocate. The facts and assumptions behind the opinion should be stated, along with material facts that detract from it. Where a question falls outside the expert’s competence, or the opinion is provisional, the report should say so. What makes the list durable is that every item is testable against the document rather than known only to the expert.
Conflicts of interest and the duty to disclose them
Independence also has a disclosure dimension. In Toth v Jarman [2006] EWCA Civ 1028, the Court of Appeal considered an expert’s failure to disclose a connection said to bear on independence. The case is routinely cited for the principle that an expert should disclose any interest or association that could reasonably be thought to affect impartiality, so that the court rather than the expert decides what weight the point deserves.
The practical reading is generous disclosure. A prior relationship with a party, earlier involvement in the same clinical episode, or a long history of instruction by one firm are better volunteered than extracted in cross-examination. A disclosed connection is usually a footnote. An undisclosed one that emerges later becomes the case against the report.
How independence shows up on the page
Independence is visible in the structure of a report, not only in its conclusions. These differences tend to matter when one report is weighed against another.
| Feature | Independent opinion | Opinion drifting into advocacy |
|---|---|---|
| Contrary evidence | Identified and weighed in the body of the report | Omitted, or acknowledged and left unanswered |
| Range of professional opinion | Set out, with reasons for preferring one view | A single view presented as the only tenable one |
| Degree of certainty | Graded, with the limits of the evidence stated | Uniformly confident across every issue |
| The other expert’s reasoning | Engaged with on its merits | Dismissed by assertion |
| Material instructions | Stated, as PD 35 requires | Not stated, or summarised selectively |
| Change of view | Communicated promptly under paragraph 2.5 | Resisted, or buried in a joint statement |
None of these is a matter of style. Each is a specific thing a report either does or does not do, which is what makes independence assessable before the report is served. The same features separate a defensible opinion from a vulnerable one, covered further in our guide to the balance of probabilities and how medico-legal opinions are expressed.
Independence and the single joint expert
Where the court directs evidence from a single expert under CPR 35.7, independence stops being a quality the parties assess and becomes the entire basis of the appointment. There is no opposing report to balance it. The mechanics of the role, including how instructions are handled when they come from both sides, are set out in our guide to what a single joint expert is and how the appointment works. The wider framework sits on our CPR Part 35 expert reports page.
What happens when independence fails
The consequences run in ascending order. At the mildest, the court prefers the other expert and says why, which costs the instructing party the issue. Above that sit adverse findings about the expert’s objectivity in a published judgment, wasted costs, referral to a regulator, and in the most serious cases contempt proceedings.
The damage is not confined to the case in which it happens. A recorded criticism is a permanent, searchable fact about an expert, and opposing solicitors look for it. We have set out how that plays out in our guide to what happens when an expert witness is criticised by the court.
How to assess independence before instructing
Most of the useful checks can be made before a page is written. Ask for a redacted sample report and read it for the features in the table above rather than for its conclusion. Ask about the balance of claimant and defendant instruction, and treat a precise answer as a better sign than a reassuring one. Ask what the expert would want to see in the records before committing to a view, because an expert who names the missing material is reasoning from evidence rather than from the instruction.
It is also worth being clear at the outset about which role is being sought. An expert instructed to advise on the strengths of a case is doing something different from an expert instructed to report to the court, and the two roles carry different duties. That distinction is set out in our guide to the difference between an expert advisor and an expert witness.
Independence is not the same as being unhelpful
There is a common misreading of all this, which is that an independent expert hedges everything and commits to nothing. The rules require the opposite. PD 35 asks the expert to reach a view and explain the reasoning, including why one position is preferred where the range of professional opinion is wide.
A valuable independent expert opinion is decisive where the evidence permits and explicit about its limits where it is not. Solicitors are not looking for an expert who agrees with them. They are looking for one whose conclusions will not move under pressure, because the reasoning behind them was sound before the pressure arrived.
Frequently asked questions
Does an expert instructed by one party owe that party any duty at all? Yes, but it is subordinate. The expert owes ordinary professional obligations, including competence and reasonable care. Where those conflict with the duty to help the court, CPR 35.3 resolves it in the court’s favour.
Can an expert change their opinion after the report is served? Yes, and PD 35 paragraph 2.5 requires the change to be communicated to the parties, and where appropriate the court, without delay. A change of view supported by reasoning is evidence of independence. Refusing to revisit one when new material undermines it is the opposite.
Does working mostly for claimants or mostly for defendants make an expert partisan? Not by itself, and a skewed instruction base breaches no rule. It is a fact that will be explored in cross-examination, which is why it is better disclosed in the report than discovered at trial.
What should an expert do if a letter of instruction asks for a particular conclusion? Answer the question actually in issue and state the material instructions received, as PD 35 requires. An instruction requests an opinion on a question, not a specific answer to it.
Related reading
- How Are Expert Witnesses Regulated in the UK?
- Understanding Causation in Complex Medico-Legal Cases
- How to Write a High Quality Expert Witness Report
Instructing an independent opinion
Where the question is whether the treatment met the standard expected, and the answer needs to survive scrutiny from the other side, the starting point is an independent medical review of the records before any report is committed to. Solicitors and claims handlers can set out the issues and the available material through the instruction page.
This article is general information about the procedural framework governing expert evidence in England and Wales. It is not legal advice or medical advice, and it does not address the facts of any particular case. Parties should take advice from a qualified solicitor on their own circumstances.