“...The importance of derivative evidence and the way that courts treat its admissibility cannot be underestimated. In many cases, the determination of whether or not derivative evidence will be admitted has the functional effect of deciding the outcome of a trial. ...” M Wiseman, “The Derivative Imperative: An Analysis of Derivative Evidence in Canada” (1997) 39 Criminal Law Quarterly 435, 491.
The fate of a criminal trial can be determined by a decision by the trial judge to exclude evidence which has come about by illegal or improper investigative means. An exclusion of a confession obtained involuntarily, or drugs located in an illegal search, can result in the collapse of a case against an accused.
Although much has been written in Australia on the rule and discretions to exclude such evidence, little has been written on a particular species of such evidence, that is, evidence which is derived from evidence which has been obtained by illegal or improper investigative means. This is so even though a criminal law practitioner is not infrequently faced with a brief of evidence which contains evidence which has been derived from other evidence which itself was illegally or improperly obtained.
Described variously in overseas literature as “derivative evidence” or “fruit of the poisonous tree”, this species of evidence gives rise to considerations which are peculiar to it when applying the exclusionary rule and discretions. Thus, the second or subsequent confession obtained after in consequence of an improperly obtained confession may require the judge to think differently on the question of exclusion. Similarly, the bank records located in consequence of scraps of paper found during an illegal search of an accused person’s residence may call into play additional factors to weigh in the balance required by the public policy discretion.
This text provides practitioners with a readily comprehensible analysis of the operation of the exclusionary rule and discretions in Australia, including the factors which come in to play generally with respect to all evidence illegally and improperly obtained, and more specifically with respect to derivative evidence.
Table of Contents
Foreword by The Hon JA Jerrard QC
The Theoretical Underpinnings of Exclusionary Powers and their Application to Derivative Evidence
The purpose of the criminal trial: The search for truth
Relevance, reliability and the criminal trial
Compromise of the search for truth
The judicial integrity principle
The deterrance principle
The protective principle
Factors of most weight in respect of the underlying principles
Derivative evidence and the underpinning theories: relevance for the practitioner
The United Kingdom Approach: Reliability and Derivative Evidence
England: From common law to PACE
PACE - general
Confessions: s 76(2) PACE
The general discretion for exclusion: Section 78 of PACE
Observations from the English experience
The US Approach: From Rights and Judicial Integrity To Deterrence
The Bill of Rights and why is it important to the exclusion of primary and derivative evidence
The Fourth Amendment - protection against unreasonable search and seizure
The Sixth Amendment - right to counsel
The Fifth Amendment - privilege against self-incrimination
Exceptions to the exclusionary rules
Conclusions: lessons from the US experience
The Australian Approach
Exclusionary powers specific to confessional evidence
Confessions under the common law
Confessions - Uniform Evidence Legislation(UEL)
The public policy discretion to exclude at common law and under statute
Factors relevant to public policy discretions
Derivative evidence with respect to confessions excluded under the confession-specific exclusionary powers
Derivative evidence in Australia - case examples
Observations on the Australian derivative cases
A suggested model for approaching derivative evidence in Australia