THE DISCRETION TO EXCLUDE ILLEGALLY OR IMPROPERLY OBTAINED EVIDENCE IN CRIMINAL CASES

• Citation: (1991) 3 SAcLJ 252
• Date: 01 December 1991
• Author: JEFFREY PINSLER
• Published date: 01 December 1991

The Court of Criminal Appeal has indicated that the principles propounded in R v Sang1 concerning the discretion to exclude evidence in criminal cases apply in Singapore.2 In How Poh Sun v PP3 the appellant had been convicted of trafficking in diamorphine and sentenced to death. The facts were that one Goh, who had been arrested the day earlier on a similar charge, had arranged for the appellant to bring the drugs to a canteen where Goh would meet him. When the appellant arrived at the canteen he was arrested by officers from the Central Narcotics Bureau. On appeal the appellant claimed that Goh was an agent provocateur4 and that this should be a relevant consideration in determining the correctness of the conviction and sentence. The Court of Criminal Appeal did not find it necessary to consider whether Goh was an agent provocateur5 as it held, on the basis of the decision in Sang, that ‘the defence of agent provocateur is not recognised in Singapore’.6

The ramifications of this decision go beyond the fact that this defence was not recognised. The Court specifically applied the certified answer of Lord Diplock7 in R v Sang which sets out the principles governing the discretion to exclude evidence in a criminal trial. The certified answer was as follows:

(1) A trial judge in a criminal trial has always a discretion to refuse to admit evidence if in his opinion its prejudicial effect outweighs its probative value. (2) Save with regard to admissions and confessions and generally with regard to evidence obtained from the accused after the commission of the offence, he has no discretion to refuse to admit relevant admissible evidence on the ground that it was obtained by improper or unfair means. The court is not concerned with how it was obtained.8

The precise scope and significance of this rule will be examined subsequently. At this stage it is appropriate to consider a case decided twenty-seven years before How Poh Sun when the Court of Criminal Appeal was faced with a similar set of circumstances. In Cheng Swee Tiang v PP9 the appellant was charged with assisting in the carrying on of a public lottery. Two police officers had entered the appellant’s shop for the express purpose of entrapping the appellant into accepting a stake, which he did. One of the issues on appeal was whether a trial court had the discretion to exclude evidence improperly obtained. Wee C.J., who delivered the judgment of the majority of the Court,10 referred to the judgment of Lord Goddard C.J. in the Privy Council case of Kuruma Kaniu v The Queen,11 the facts of which concerned an illegal search of the accused’s person. Lord Goddard formulated the rule of discretion as follows:

No doubt in a criminal case the judge always has a discretion to disallow evidence if the strict rules of admissibility would operate unfairly against the accused … if, for instance, some admission of some piece of evidence, e.g., a document, had been obtained from a defendant by a trick, no doubt the judge may properly rule it out.12

Wee C.J. concluded that it was ‘undisputed law’ that there is a judicial discretion to exclude relevant evidence if its reception ‘would operate unfairly against the accused’.13

… two important interests come into conflict when considering the question of admissibility of such evidence so obtained. On the one hand there is the interest of the individual to be protected from illegal invasions of his liberties by the authorities; and on the other hand the interest of the state to secure that evidence bearing upon the commission of crime and necessary to enable justice to be done shall not be witheld from the courts on any merely technical ground …14

As the Court allowed the appeal on other grounds it left open the question of whether the evidence ought to have been excluded in the circumstances of the case. Ambrose J. dissented because he did not accept that such a discretion could exist in the absence of an express provision in the

Evidence Act15 granting such power.16 However, he expressed the view that even if the court had such a discretion it would not have been correct to exercise it in the circumstances of the case. The majority of the court did not indicate what the right circumstances for the exercise of the discretion might be. Ambrose J. thought that the discretion might have been exercised if the evidence had been obtained ‘oppressively, by false representations, by a trick, by threats, by bribes, or anything of that sort’.17

The significance of the decision in Cheng Swee Tiang is that it recognised that the discretion to exclude could be exercised to exclude evidence improperly obtained. As Wee C. J. stated, it was a question of balancing the interest of the individual against illegal invasions of his liberties by the authorities and the interest of the state to secure relevant evidence.18 He concluded as follows:

It seems to me, both on principle and authority, that no absolute rule can be formulated and the question is one depending on the circumstances of each particular case.19

The purport of this statement is clear: there could be circumstances in which the balance would fall on the side of the accused with the result that the discretion would be exercised in his favour. In Callis v Gunn20 Lord Parker C.J. referred to the rule in Kuruma and indicated that the ‘strict rules of admissibility would operate unfairly against the accused’ if the evidence ‘had been obtained in an oppressive manner by force or against the wishes of the accused’ and if it had been ‘obtained oppressively, by false representations, by a trick, by threats, by bribes …’21 In Jeffrey v Black22 Lord Widgery C.J. referred to the discretion as applying to all the evidence which is tendered by the prosecution (not just evidence obtained from the accused):

… if the case is such that not only have the police officers entered without authority, but they have been guilty of trickery or they have misled someone, or they have been oppressive or they have been unfair,

or in other respects they have behaved in a manner which is morally reprehensible, then it is open to the justices to apply their discretion and decline to allow the particular evidence to be let in as part of the trial.23

In neither Callis v Gunn nor Jeffrey v Black was the discretion to exclude exercised. Nevertheless the views expressed in these cases were considered by the House of Lords in R v Sang24 as setting the scope of the discretion too widely.25 Lord Diplock regarded the dicta in these cases as being based on a ‘misunderstanding’ of Lord Goddard’s dictum.26 Lord Scarman pointed out that ‘he would not necessarily dissent from them’ if they ‘were treated as relating exclusively to the obtaining of evidence from the accused’.27 The House of Lords in Sang adopted a different construction of the dictum in Kuruma. The issue for consideration in that case, as in Cheng Swee Tiang and How Poh Sun, was whether the courts had the discretion to exclude evidence obtained by an agent provocateur. The House of Lords held that the use of an agent provocateur did not give rise to a discretion to acquit the accused, nor to a discretion to exclude evidence of a crime merely because the crime was instigated by the agent provocateur.28 Lord Diplock interpreted Goddard L.J’s statement in Kuruma as follows:

That statement was not, in my view, ever intended to acknowledge the existence of any wider discretion than to exclude (1) admissible evidence which would probably have a prejudicial influence on the minds of the jury that would be out of proportion to its true evidential value and (2) evidence tantamount to a self-incriminatory admission which was obtained from the defendant, after the offence had been committed, by means which would justify a judge in excluding an actual confession which had the like self-incriminating effect.29

This statement also appears in Lord Diplock’s certified answer.30 Of the first category, Lord Diplock said that a trial judge in a criminal trial always has a discretion to refuse to admit evidence if its probative value is outweighed by its prejudicial effect.31 His Lordship reviewed the authori-

ties and concluded that the principle, although initially confined to certain areas of evidence, had now developed into a general rule of practice.32 The second category is formulated in the certified answer as ‘admissions and confessions and generally with regard to evidence obtained from the accused after the commission of the offence’.33 This second category does not, of course, affect the rules of law which automatically exclude confessions and admissions which are involuntary.34 Both categories are concerned with evidence that would ordinarily be admissible. The basis for the discretion to exclude evidence in the second category lies in the maxim ‘nemo debet prodere se ipsum’ or ‘no one can be required to be his own betrayer’.35 Accordingly, if, for instance, the accused is improperly induced by the police to give them an incriminating document or to give a sample of his blood for examination, the court would have the discretion to exclude such evidence. In R v Barker36 it was held that incriminating documents (showing that the accused had committed fraud) obtained from the accused by the promise of favours were inadmissible. Although the evidence was excluded as a matter of law,37 Lord Diplock preferred to treat the case as illustrating the discretion to exclude in the circumstances of the second category.38 In R v Payne,39 also cited by Lord Diplock as an illustration of the second category, the accused was charged with driving while unfit through drink. He was induced into submitting himself to a medical examination to determine whether he was suffering from an illness or disability. The accused agreed on the understanding that the doctor would not examine him for the purpose of determining whether he was fit to drive. At the...