The exclusionary rule of English law and its proper characterisation in the conflict of laws – is it a rule of evidence or contract interpretation?

Abstract

In accordance with the so-called exclusionary rule (and in contrast to civil law jurisdictions and international instruments), English law considers previous negotiations, declarations of subjective intention and subsequent conduct of contractual parties inadmissible for the purposes of contractual interpretation. This poses a problem of characterisation in international commercial disputes: if the exclusionary rule might, in accordance with the private international law of the forum be characterised as a rule of procedure (concerning evidence) rather than of substance, foreign courts and arbitral tribunals should not apply this rule even if English law is the governing law of the contract. It is argued that, contrary, to the prevailing view, the characterisation of the exclusionary rule as a rule of evidence is justified: though its application may doubtlessly affect the material outcome of a given case, the exclusionary rule has no bearing on the method of interpretation itself and is hence not directly concerned with matters of interpretation.