A recent Upper Tribunal decision gives some unusually practical guidance for experts who rely on material found online.

In SU (Expert reports – format) Bangladesh [2026] UKUT 317 (IAC), the Tribunal considered expert reports which drew heavily on publicly available internet material. The decision is particularly useful because it deals with something that now affects experts in many fields: how to use online source material properly in an expert report.

The Tribunal’s guidance is fairly straightforward, but important.

Where an expert relies on material found online, the source should be identifiable and capable of being checked. So far as possible, the expert should use the primary source rather than a secondary report about it. If material is quoted, it should be clearly identified as a quotation, with a link to the source and a translation where appropriate.

That is the sourcing side of the exercise.

But there is a separate point which is perhaps more important.

The material found online is not the expert opinion.

It is source material from which the expert may form an opinion.

The expert’s task is to consider that material, explain its relevance and significance, and then form and express an independent opinion based on it.

Both parts matter.

The underlying source material must be sufficiently transparent for the court or tribunal to understand where it came from and, where necessary, check it. But the report must also show the expert’s reasoning. The court needs to be able to understand how the expert moved from the underlying facts and sources to the opinion ultimately expressed.

It is then for the court or tribunal to decide what weight to give that opinion.

Primary sources matter

One point made expressly by the Upper Tribunal is that experts should, where possible, go back to the original source.

That may sound obvious, but it is increasingly easy to rely on a newspaper article, online summary, social media post or another secondary source which itself refers to an underlying document.

For an expert, that can create unnecessary uncertainty.

If a government statement, NGO report, technical paper, regulatory document or other primary material exists, there is obvious value in identifying and considering that material directly.

The Tribunal also stressed the importance of making quotation clear. Material copied from elsewhere should not appear in the report as though it were the expert’s own words.

That is not simply a matter of presentation. It enables the reader to distinguish between:

• the underlying source;
• the facts or information derived from it;
• the expert’s analysis of that information; and
• the expert opinion.

Those distinctions are central to a properly reasoned expert report.

The Academy’s own guidance on the Model Form of Expert Report reflects the same need to distinguish clearly between matters of fact and opinion.

Applying the material to the case

The Tribunal also made clear that a report should do more than set out general material.

Where the expert has been asked to consider the particular circumstances of a party, the report should apply the expert’s general conclusions to those particular facts.

That is an important part of what makes the evidence expert evidence rather than simply research.

A court can often read source material for itself. The value of the expert lies in the specialist analysis and opinion brought to that material.

That may involve explaining technical significance, identifying limitations, placing information in context, drawing on professional experience or explaining how apparently conflicting material should be understood.

The Academy’s What is an Expert Report? guidance similarly stresses that an expert report is not merely a statement of conclusions. The factual basis and reasoning leading to the opinion matter.

Responding to criticism

There is another useful practical point in SU.

Where one of the parties has raised concerns about an aspect of the expert report, the Tribunal said the expert should address those concerns directly, bearing in mind the overriding duty to assist the Tribunal on matters within the expert’s expertise.

That matters because an expert’s duty is not to defend the report at all costs.

If a legitimate criticism identifies an error, omission, weak source or assumption which needs reconsideration, the expert should deal with it.

The Academy’s Code of Practice for Experts places independence, impartiality, objectivity and integrity at the heart of expert practice.

A practical consequence of the online world

The volume of information available to experts has changed enormously.

In many fields, an expert can now locate hundreds of sources in a relatively short period. That can be extremely useful, but volume is not the same as quality.

The discipline lies in showing:

• what material has actually been relied upon;
• where it came from;
• why it is relevant;
• what the expert makes of it; and
• how it contributes to the opinion expressed.

That is why traceability matters.

The court or tribunal does not simply need an expert who can find information. It needs an expert who can analyse that information, explain it and give a properly supported opinion within their expertise.

That is the useful lesson from SU (Expert reports – format) Bangladesh.

Decision:
https://tribunalsdecisions.service.gov.uk/utiac/2026-ukut-00317

BAILII:
https://www.bailii.org/uk/cases/UKUT/IAC/2026/317.html

Related Academy resources

• Model Form of Expert Report
• What is an Expert Report?
• Code of Practice for Experts
• The Expert’s Report training

The High Court’s judgment in Various Claimants v Mercedes-Benz Group AG and others [2026] EWHC 1753 (KB) is a useful reminder that technical expertise, however impressive, is only part of the job of an expert witness.

The litigation involved a huge amount of highly technical expert evidence across a number of disciplines. What is particularly interesting is the contrast in the judge’s assessment of the experts themselves.

Some were praised for the quality and fairness of their evidence. Others attracted criticism over aspects of their compliance with Part 35.

That contrast matters because the experts involved were not lacking in technical expertise. They were experienced specialists dealing with complex issues in major litigation.

The point is rather that being an expert in your field and being an effective expert witness are not quite the same thing.

Under CPR Part 35, an expert’s role is to assist the court on matters within their expertise. That duty overrides any obligation to the person instructing or paying them.

Practice Direction 35 goes further. Expert evidence should be the independent product of the expert, uninfluenced by the pressures of litigation, and experts should consider all material facts, including those which might detract from their opinions.

Those requirements affect far more than the declaration at the end of a report.

They affect how the expert approaches the evidence in the first place.

An expert needs to be able to distinguish between what they know, what they have been told and what they have inferred. They need to consider material which may not support the position of the party instructing them. They need to explain the basis for their conclusions and, where appropriate, acknowledge that there may be a legitimate range of professional opinion.

Perhaps most importantly, they need to remain willing to reconsider their conclusions as the evidence develops.

That may sound elementary to experienced expert witnesses. But the significance of the Mercedes-Benz judgment is that these issues arose in extremely sophisticated litigation involving highly experienced specialists.

The technical complexity of the subject matter did not lessen the importance of the expert’s procedural and professional duties.

If anything, it made them more important.

Where the underlying issues are difficult for a court to evaluate without specialist assistance, the court is particularly dependent upon the expert presenting that specialist knowledge independently, fairly and in a way that can be understood and tested.

That is why the quality of expert evidence cannot be measured simply by the expert’s qualifications or standing in their profession.

The court also needs to be able to trust the process by which the opinion has been reached.

The Academy’s guidance on party-appointed experts reflects this. The expert’s role is to provide unbiased opinion within their expertise and not to assume the role of advocate.

The Academy’s Code of Practice for Experts similarly places independence, impartiality, objectivity and integrity at the centre of expert practice.

And because much of the expert’s evidence will ultimately be contained in the report, the Academy’s Model Form of Expert Report is designed to help experts present their reasoning in a form which assists the court. The Academy’s The Expert’s Report training also deals specifically with compliance, professional guidance and the practical preparation of expert evidence.

The broader lesson from the Mercedes-Benz litigation is fairly simple.

An expert witness brings two kinds of expertise to court: expertise in their professional field, and expertise in performing the role of an expert witness.

The first does not automatically provide the second.

Judgment

A High Court decision provides a useful warning for professionals who become expert witnesses in matters in which they have already been involved.

In MSA Properties Ltd v The Drapery Northampton Ltd [2026] EWHC 1420 (KB), the court had to resolve a dispute concerning deteriorated structural joists in a building in Northampton. Both parties relied on structural engineering evidence.

The point of wider interest for experts concerns the defendant’s expert, who had already been involved in the matter before the litigation.

He inspected the building in 2023 and produced a report for the defendant. That report was not prepared as expert evidence for the proceedings. By 2025, however, he was acting as the defendant’s expert witness.

That change of role became important.

The judge noted that the later expert report did not refer to the earlier inspection or the report produced at the time, despite the expert accepting in oral evidence that the earlier inspection had given him a better view of the joists.

The court was also critical of the extent to which he had engaged with the available evidence and of the opportunities available to him to inspect the property more fully.

The most significant criticism was the judge’s observation that his approach reflected:

“some conflation of his role as a contractor engaged in negotiations with the Claimant and his duties as an expert witness”

There was no suggestion that the expert had deliberately acted partially. The concern was rather that aspects of his earlier role appeared to have carried over into the way he approached his later expert evidence.

That is a useful warning for any professional who changes role during the life of a dispute.

Previous involvement does not automatically prevent someone from later acting as an expert witness. In some cases, that earlier involvement may mean they have valuable knowledge of the subject matter.

But the nature of the role changes.

A contractor, consultant or adviser may previously have been helping a client solve a problem, negotiate a position or achieve a particular commercial outcome. An expert witness has a different duty.

Under CPR 35.3, an expert’s duty is to help the court on matters within their expertise. That duty overrides any obligation to the person from whom they have received instructions or by whom they are paid.

That is not simply a formal statement to be repeated in the declaration at the end of a report. It has practical consequences for the way an expert approaches the evidence.

Transparency about previous involvement

Where an expert has already inspected the subject matter, produced reports, advised a party, taken part in negotiations or expressed views before being instructed as an expert witness, that history may be material to the opinion now being given.

The point is not that every earlier conversation or document must automatically be reproduced. It is that relevant prior involvement should not be left invisible if it bears on the expert’s present reasoning.

That is particularly important because CPR 35.10 requires an expert report to state the substance of all material instructions, whether written or oral, on the basis of which the report was written. Practice Direction 35 also requires the expert to make clear which facts are within their own knowledge and which have been provided by others.

In this case, the earlier involvement was not peripheral. The expert had inspected the joists at a time when they were more fully exposed and had produced an earlier report. He later accepted that the earlier inspection had given him a better view of the joists, yet neither the inspection nor the earlier report appeared in his expert report.

That is a useful illustration of why disclosure matters.

If earlier involvement has informed what the expert knows, assumes or concludes, the court should be able to see that route clearly. If it only emerges later, particularly in cross-examination, the omission can create an avoidable question about the completeness and transparency of the expert’s reasoning.

For an expert changing role, a sensible question at the outset is:

What have I already done, seen, said or concluded in this matter, and what of that is material to the opinion I am now giving?

If someone changes role during the life of a dispute, earlier assumptions may need to be revisited. Previous opinions should not simply be carried forward without being tested against the evidence now available. Earlier inspections, reports and involvement may themselves be relevant and should be dealt with openly where necessary.

The wider framework of the Civil Procedure Rules matters as well.

The overriding objective in CPR 1.1 is to enable the court to deal with cases justly and at proportionate cost. Expert evidence forms part of that process. It is therefore not enough for an expert merely to possess relevant expertise. The evidence has to assist the court in a way which is independent, properly reasoned and proportionate to the issues in dispute.

That is why a change in role can be important.

A professional may quite properly have spent months or years advising a client, negotiating with another party or working towards a particular practical outcome. Those activities may require judgement, persuasion and a close identification with the client’s interests.

The expert witness role is different.

Once instructed as an expert, the professional must be able to step back from that earlier involvement and approach the evidence independently. That may mean reconsidering previous views, acknowledging matters which do not support the client’s position and making clear where earlier involvement has informed the present opinion.

• The Academy’s guidance on party-appointed experts explains the overriding duty owed by an expert to the court.
• The Academy’s Code of Practice for Experts places independence, impartiality, objectivity and integrity at the heart of expert practice.
• The Academy’s Model Form of Expert Report is also relevant where an expert has had previous involvement, because the report should make clear the factual basis of the opinions expressed and the material relied upon.

The lesson from MSA Properties is not that previous involvement disqualifies an expert. It is that a professional who moves from contractor, adviser or negotiator to expert witness must make that transition consciously and transparently. The court may look closely at whether the expert has genuinely separated the new role from the old one, and whether the report gives a clear account of any earlier involvement which bears on the opinion now being expressed.

For experts, that is a useful point to consider before accepting instructions in a matter in which they have already been involved.

See the judgment here on BAILII.

Some specialist areas of expertise are so niche that it’s almost impossible to find experts who are free of previous involvement with one or more parties to a dispute. In a recent case requiring expert evidence in mine surveying (Cleveland Potash Ltd v Drummond & Ors) not only had both experts been involved with the parties they had worked in the same office as each other for 20 years!

In this case both experts were clear and transparent about their previous involvement and as the  judge explained, “Whilst neither party raised any concerns about the experts’ prior and ongoing involvement in the issues related to this dispute I will have to consider that involvement as part of my overall assessment of the experts. I remind myself that the experts have an overriding duty to the court which should override their duty to their clients.”

It seems that one expert was much more successful in retaining her objectivity than the other, reading the judge’s explanation gives some important pointers for all experts as to how to do this, specifically;

“Mrs Iwanicki was a very impressive witness. She was deeply knowledgeable about her subject. She gave clear, careful, well considered and measured answers to the questions she was asked. She had a good understanding of her overriding duty to assist the court rather than to advocate for a particular position. Her answers were honest and straightforward even where those answers might have been seen as providing some assistance to Rs. That is what the court expects of an expert witness who understands that their role is not to advocate for a particular party or outcome but to assist the court.

 

Mr Troman was also clearly very knowledgeable about his subject, however, unlike Mrs Iwanicki on some occasions he did not appear able to disassociate his longstanding role of assisting the Rs (and other leaseholders) to negotiate what he considered to be a satisfactory outcome with CPL from his duty to assist the court. This more partisan approach had infected some of his evidence and the contents of his report. It was clear from his evidence that he felt that other mineral rights owners who had now agreed terms with CPL should have held out and/or would have done better if they had followed his advice/recommendations. He was reluctant to accept the possibility that the conclusions in his report might need to be adjusted or modified even when it became apparent that there were factors or information that he had not known about and could not therefore have taken into account when reaching his conclusions. His resistance to accepting any possibility that his conclusions on valuation might need to be adjusted was unhelpful and undermined his position. Further he had a tendency to speculate both in his report and in his evidence and on at least one occasion asserted a factual position which turned out not to be true. Overall, this approach undermined his credibility and the weight that I give his expert opinion.

 

As always the key for any expert is to ask yourself ‘what would I say if I was acting for the other side?’. If the answer is in any way different then you need to think again. For guidance on what to do if you have been involved with a party to a dispute and other issues relating to conflicts or perceived conflicts see our guidance on the subject.

Our image is from the New Scientist

 

The High Court ruling against Danish tax authority SKAT in a £1.4 billion dividend tax fraud case has been widely reported, not least because the judge concluded that SKAT’s controls on the transactions involved were so flimsy as to represent the equivalent of a ‘help yourself’ sign outside a bank.

 

Less attention has been given to the judge’s criticisms of the experts who appeared on behalf of the many parties involved. As he put it “ All three experts, in differing ways, did not provide properly balanced written reports”.

 

Perhaps the clearest example was SKAT’s expert “whose written work was argument rather than expert evidence” showing the dangers of working closely with a client and legal team on complex, long-running litigation. The judge concluded that “he finds it difficult not to think and express himself as an advocate for SKAT’s position. He has, I think, lost detachment from the partisan interests of SKAT” and was unable perhaps to hear any ‘evil’ in his client’s case.

 

Somewhat less concerning was an expert whose testimony was careful but tended to obscure his views and maximise differences with other experts that were not a pronounced as appeared at first glance.  As the judge observed, “That exposed him to a cross-examination that should have been largely unnecessary to confirm the extent to which, in substance, he agrees with a range of matters on which SKAT relied. “ Fortunately he appears to have dealt with that cross-examination impressively, fairly (with balance), and with an obvious depth of thought and expertise. A better approach might have been to write a report that allowed the parties to see more clearly.

 

And finally, the third expert’s generally much better approach (once his reports had been edited to remove contentious factual matters that should not have been there!) and thoughtful and fair answers to questions were undermined by his taking a view in the witness box that he had not expressed in writing.  The judge concluded that his interpretation of a key terminology expressed in oral evidence “had not been his view at any material time. It was inconsistent with the views he had expressed in writing, including in his primary expert report in these proceedings, to which he had to proffer alterations when called to give his oral evidence to advance the different view. “  While the case did not turn on this point the judge made it clear that speaking out in this way, because his written views in fact assisted the other side, was not acceptable and did the expert no credit.

 

The message to experts should not be a surprise, no client’s case is perfect and there are times when your views will not support their case. When that happens it is critical that you make sure your client’s hear you, that the court can see hat your views really area and that when you speak you keep your duty of independence firmly in mind.

Anyone considering acting as an expert needs to understand that environment,  the rules that apply to expert evidence and how to avoid the pitfalls that can lead to a difficult time in court and potentially public criticism from a Judge.

The Academy’s training programme is designed to help already  skilled professionals through the basic foundations to a mock cross-examination to ensure that they are fully prepared. Our training courses are primarily delivered online but we run some face to face courses  in London and Hong Kong. We can also run in-house training for larger consultancies, please contact us for details.

Given how  often lawyers and experts complain about encountering hired guns in litigation it sometimes seems that every other expert must be crossing the line from independent, objective opinion into full-blown bias and advocacy for their client.

In reality our adversarial system means that any expert other than a Single Joint Expert will spend a good deal more time with their own client and legal team than the opposition . Your legal team will typically be more interested in picking holes in the other side’s arguments and expert reports than checking that your report is 100% objective so it’s easy to slide, almost unconsciously, into positions that favour your side.

Judges understand this to some extent and  as long as the bias is not too extreme may confine themselves to a wry comment. For example, “Both experts on occasions were over-optimistic in favour of the party who instructed them.” and “both experts at times had seemed, at least in their reports, to have adopted a rather more critically rigorous approach to assessing the quantum of the other parties’ claims than when reviewing their own client’s.”

But expert evidence is very important to the courts and experts are rightly held to very high standards, so a good starting point to is to try to avoid even such mild criticism. The simplest way to do this is to read your own report  as though you were the other side’s expert. Are there gaps in your reasoning? Is there evidence  that might contradict your conclusions? If you’ve discounted witness evidence or documents, why have you done that? Is it justified?  Have you set too high or too low a standard for professional conduct in your analysis?

The key question is does this report help the judge to understand the case and form a truly objective view of the expert issues. Then when you arrive in court you will be confident that your report will stand up to even the most difficult cross-examination.  In a recent case, for example,  a valuation expert who the judge considered to be unquestionably an impressive expert was subjected to trial by ambush while giving evidence. Fortunately his expertise and independence mean that when “presented with new material while in the course of giving evidence; he engaged with the new figures presented to him and was able to offer clear, comprehensive answers to the questions put

By contrast in a clinical negligence case an expert had based all her opinions and written her report entirely based on fact that was not stated in a witness statement and had been completely undermined during the trial. The judge commented that she found this very concerning, “as it appeared to me that the expert was:

i) holding firmly to an opinion which was based on one perceived fact which she elicited from the Second Defendant’s witness statement (that he had the diagnosed pyelonephritis in mind at the index consultation, albeit that his witness statement was clear at the start that he had no recollection of the Claimant at all), even when the basis of that perceived fact had been fatally undermined;

ii) trespassing on the judicial function to find, and rely on as a fact (or as her belief) that he was considering pyelonephritis in the index consultation; and

iii) seeking to advocate on behalf of the Second Defendant, thus undermining her own independence. “

 

Unsurprisingly the other expert’s evidence was preferred, something that  could easily have been avoided by a careful and considered review of the report and the evidence by the expert and her client’s legal team.

 

The Academy’s Judicial Committee publishes the authoritative guidance for experts so you can be sure that you are adopting best practice. This includes for example the Model Form of Expert’s Report and Guidance Notes on Meetings of Experts, Contingency Fees & Remote Evidence. We also provide practical advice and guidance on topics such as GDPR, Joint Statements, privilege and so on which is available at no charge to members in the Academy’s Knowledge Hub.

Our image is from GOG.com

To kick off 2025 we’re starting a new series of posts about terms and expression used by lawyers that can leave the new expert rather baffled. You may well hear references to the Ikarian Reefer bandied around and wonder what on earth that has to do with medicine, construction, accountancy or science.

On 12 April 1985 a ship called The Ikarian Reefer ran aground on shoals. There was subsequently a court case heard by Mr Justice Cresswell (as he was then). He found some of the evidence presented to him to be unsatisfactory and established principles in his judgement for expert evidence. Essentially he laid out that expert evidence should be

1. independent, uninfluenced, objective and unbiased

2. within the individual’s expertise, with any questions falling beyond that clearly identified

These later formed the basis of the UK civil procedure rules (and others). For more information on the role of an expert see https://academyofexperts.org/practising-as-expert/

(our image is from http://shipspotting.com)