The CV is exactly what the tribunal wants: doctorate, publications, courtroom experience, working English. The report is solid. And the first question opposing counsel asks at the hearing is not about Article 551 or the Cape Town Convention — it is about a textbook your expert co-authored in 2014 with the other side’s expert, or a supervision committee they both sat on.
Contents
This article is about that moment: why it is structurally more likely in Ukraine than in large jurisdictions, which relationships actually destroy an expert report and which merely decorate a cross-examination, and why the answer is almost never «find someone with no links» — because on this market, that person does not exist.
Small market is a legal fact, not a demographic note
The pool of Ukrainian lawyers who can credibly give expert evidence abroad — doctorate, a live publication record, procedural English, courtroom stamina — is small, and its members have spent decades crossing paths: the same university departments, the same dissertation councils, the same handful of conferences, co-authored commentaries, successive editions of the same treatise. The aviation-finance, investment-arbitration and commercial-disputes communities overlap heavily.
None of that makes anyone dependent. What it changes is the arithmetic of disclosure: on a market this size, the probability that your expert has some traceable link to a party, a counsel team or the opposing expert approaches certainty. So the question a careful instructing counsel asks is not «is there a connection?» — there is — but «which connections matter, and has every one of them been put on the table before the other side finds it?»
The duty is to the tribunal — everywhere that matters
Under CPR Part 35, the expert’s duty to help the court overrides any obligation to the person instructing or paying them. Under the IBA Rules on the Taking of Evidence (2020), a party-appointed expert’s report must disclose any and all relationships with the parties, their legal advisers and the tribunal (Article 5.2(a)) and carry a statement of independence from all three (Article 5.2(c)).
One confusion is worth clearing at the start, because it costs money: the IBA Guidelines on Conflicts of Interest — the traffic-light lists — govern arbitrators, not experts. For experts there is no automatic disqualification grid. Undisclosed bias goes to weight, not admissibility. That sounds forgiving until you remember what an expert report is for: weight is the only thing it has. A report whose author survives admissibility but loses credibility has cost you a fee and armed the other side.
For Ukrainian proceedings the same logic applies with a local twist: an opinion of an expert in the field of law is advisory by statute and never binds the court — so its entire value is persuasive weight, and a credibility wound is fatal by definition.
A field guide to the links
| The link | Kills or survives? | What to do |
|---|---|---|
| Prior advisory or transaction work for a party (or its affiliate) on the matter now in dispute | Usually kills the appointment | Decline, or obtain informed positions of both sides early; this is the conflict people miss years later |
| Ongoing work for the instructing law firm | Survives with disclosure | Disclose the relationship and its scale; a «house expert» pattern erodes weight with every repeat appearance |
| Co-authorship or shared faculty history with the opposing expert | Survives with disclosure | State it in the report before anyone asks; concealed, it becomes the EXP v Barker scenario below |
| Doctoral supervision across the aisle — your expert examined or supervised the other side’s expert | Survives with disclosure | Disclose; prepare the expert for theatre on cross, which is what this is |
| A published position on the very question in issue | Not a conflict — a prior commitment | Disclose and address it head-on; a consistent published position defended for years is an asset, an unexplained reversal is not |
| Past appointments as arbitrator or counsel in the same party’s other cases | Forum-dependent | Disclose and let the tribunal weigh it; concealment converts a neutral fact into a credibility issue |
The pattern in the right-hand column is not subtle. On a small market, almost everything survives daylight — and almost nothing survives being discovered by the other side first.
EXP v Barker: the cautionary tale
The English Court of Appeal supplied the textbook case. In EXP v Barker [2017] EWCA Civ 63, the defendant neuroradiologist relied on an expert who had trained him, mentored him and co-authored papers with him — and none of it was disclosed. The relationship surfaced in cross-examination. The Court of Appeal held the trial judge was fully entitled to treat the expert’s evidence as carrying «considerably diminished» weight — and added that outright exclusion would also have been upheld.
Read the facts against the table above: the link itself sat in the «survives with disclosure» row. What killed the evidence was not the mentorship — it was the concealment. That is the precise lesson for a market where mentorship chains connect half the profession.
Disclosure beats purity
There are no unconnected experts here; there are disclosed and undisclosed connections. So the working method is mechanical. The relationships map in the report follows Article 5.2(a) — parties, counsel, tribunal, opposing expert, prior positions in print. The statement of independence follows 5.2(c) and means what the commentary says it means: no financial interest in the outcome, no relationship that prevents an honest opinion. And where a prior role makes independence genuinely contestable — not merely colourable — the honest move is made before instruction, not after: we have declined expert appointments where earlier transaction work for a party would have made the independence statement arguable.
How the check runs here
Before any confidential detail changes hands: the names of the parties and their known affiliates, the opposing counsel teams if known, the transaction or dispute in outline, and the Ukrainian law questions at issue. The conflict check runs the same day; the answer comes back in writing. Only then does the instruction letter follow. For the instructing counsel this costs one short email — and it is the single cheapest insurance in the entire engagement.
The wider selection criteria — degrees, publication records, what tribunals actually weigh — are covered in Ukrainian Law Expert Witness: What Surprises Foreign Counsel; the service itself is described at Expert Witness on Ukrainian Law.
Questions we are asked
Can the same firm act as counsel and expert in one proceeding?
No — the two roles are incompatible within a single case: counsel argues a party’s position, an expert owes the tribunal an independent one. The same firm can hold either role in unrelated matters, which is exactly why the conflict check asks about related proceedings.
Does co-authorship from a decade ago disqualify an expert?
No. Undisclosed co-authorship does. The passage of time reduces the sting only if the relationship is on the table from the start.
Our candidate has published on the exact question in dispute. Problem?
The opposite, usually — if handled openly. A position defended in print for years is hard to dismiss as made-to-order. What damages credibility is an unexplained departure from the expert’s own published view; if the position has evolved, the report should say why.
Do the IBA Guidelines on Conflicts of Interest apply to experts?
No — they govern arbitrators. For party-appointed experts the operative standard is Article 5.2 of the IBA Rules on the Taking of Evidence: full disclosure of relationships and a statement of independence. Different instrument, different consequence: for experts, the sanction is weight.
Who signs expert reports at JVS Law?
The partner who gives the evidence — Anna Tsirat or Gennadii Tsirat, both Doctors of Laws, with appointments before the PCA in The Hague and the High Court in London. We work on this market, we know its map of connections — which is precisely why our reports disclose first and argue second.
What does an engagement start with?
The conflict check, same day, in writing. Then scope, questions, forum rules and timetable. A partner replies within one business day.
Written by Anna Tsirat, Doctor of Laws, partner at JVS Law. Appointed as an expert on Ukrainian law in proceedings before the Permanent Court of Arbitration in The Hague; author of Kluwer Law International publications.
Published 30 September 2026. CPR Part 35 and the IBA Rules on the Taking of Evidence are cited as in force at the date of publication; tribunal practice on expert independence develops — check the forum’s current standard before an appointment.