Admissibility of Illegally Obtained Evidence in International Commercial Arbitration

by Varshini Sunder, 4th-year student, HNLU

Evidence in international commercial arbitration can be admitted at the sole discretion of the Arbitral Tribunal. There are no rules concerning the admissibility of illegally obtained evidence in specific. Generally, the only criteria the evidence must meet is the test of relevance and materiality.[i] While there are no reported instances of commercial arbitrations on illegally obtained evidence, the plethora of decisions in the international investment forum may throw some light on the issue.

However, unlike investment arbitrations, public interest is not a matter of concern in commercial arbitration as both parties are individuals with private interests. Therefore, documents which would tip the scales in the name of public interest and support admission, will not reach the same conclusion in commercial arbitrations.

In the case of Caratube International Oil Company LLP v. Republic of Kazakhstan[ii], the claimant sought to rely on certain privileged documents that were published on a website after the Kazakh Government’s network was hacked. The Tribunal allowed this evidence to be admitted stating that “it should not be deprived of any evidence which is in the public domain.”

This gives us an indication that evidence in the public domain, albeit illegally obtained, can be admitted before Tribunals. However, this gives rise to another notorious question, what constitutes public domain?

While WikiLeaks released several confidential and privileged information into the public domain, one wouldn’t know whether a particular document is, in fact, available on it, unless its entire data is rummaged through. Therefore, although it is in the public domain, in theory, it is not known to the people at large, and therefore is not in the public domain in the real sense. This was the rationale adopted in Wee Shuo Woon v. HT S.R.L.[iii] where the email sought to be admitted was not deemed to be in public domain merely because it was published by WikiLeaks. It stated that,

“Merely making confidential information technically available to the public at large does not necessarily destroy its confidential character. Public media, in particular the Internet, must not be the gateway through which all confidentiality is dissolved and destroyed.”

The case also stressed on the general duty of confidentiality which is imported when a person receives information he knows to be confidential as elucidated on in the Attorney-General v. Guardian Newspapers (No 2)[iv]. This is reasonable as the confidentiality of a document must be protected as long as it is not entirely stripped of it.

Admitting illegally obtained evidence could have certain implications on the procedural fairness of the proceedings. Therefore, the ethical standards which the tribunal ought to maintain must not be vanquished. A doctrine to validate illegally obtained evidence in arbitrations is the “clean hands doctrine”. According to this approach, the “possible unlawful nature of the disclosure” of the evidence cannot be held against a party which wants to place reliance on such evidence and, was not involved in its illegal disclosure.[v] Therefore, as long as the person who seeks to admit the information was not engaged in its procurement, the evidence must be admitted.

A striking example of lack of clean hands is the Methanex Corp. v. USA[vi] case wherein the Claimant searched through the dumpsters of the office of a lobbying organization to obtain certain notes and correspondence. This case of dumpster diving was held to violate the equality of arms between parties and principles of natural justice and fairness they ought to maintain.

The clean hands approach though reasonable does not absolve the evidence of its illegal source. While the “fruit of the poisonous tree” doctrine is usually adopted in criminal cases, some commentators in recent times have advocated its application to civil cases as well.[vii] Since the evidence is still tainted by some illegality, it could run contrary to the public policy of the country where enforcement is sought, rendering the award unenforceable.

The repercussions of admitting such evidence, are [viii]however, frightening. It could incentivize people to procure more such privileged and confidential information unlawfully should find that their admissibility isn’t problematic. The rationale behind doing away with strict rules of evidence in international commercial arbitrations was to minimize the formalities and increase the tribunal’s efficiency, not to trivialize the law and encourage its transgression.  Therefore, the Tribunals must always weigh and balance the competing conflicting interests cautiously while determining matters of admissibility as its effects are manifold.


[i] Article 19(2), UNCITRAL Model Law on International Commercial Arbitration (1985 with amendments adopted in 2006).

[ii] Caratube International Oil Company LLP v. Republic of Kazakhstan, ICSID Case No. ARB/13/13.

[iii] Wee Shuo Woon v. HT S.R.L., [2017] SGCA 23.

[iv] Attorney-General v. Guardian Newspapers (No 2), [1990] 1 AC 109.

[v] Blair, Cherie & Gojkovic, Ema Vidak, Wikileaks and Beyond: Discerning an International Standard for the Admissibility of Illegally Obtained Evidence, 33 ICSID Review 235-259 (2018).

[vi] Methanex Corp. v. USA, (2005) 44 ILM 1345.

[vii] Cooper, Nigel, The Fruit of the Poisonous Tree – The Admissibility of Evidence in Civil Cases.

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