R v Sang

Factual and Procedural Background

The Appellant was tried at the Central Criminal Court for conspiracy to utter counterfeit United States banknotes. Before the jury was sworn, counsel alleged that the offence had been instigated by a police informer acting as an agent provocateur and invited the trial judge (“Judge Buzzard”) to hold a “trial within a trial” to determine whether, on that footing, the prosecution’s evidence should be excluded. Relying on prior authority that entrapment is no defence under English law, the trial judge ruled that even if the alleged inducement were proved he had no discretion to exclude otherwise admissible evidence. The Appellant thereupon changed his plea to guilty and received an 18-month custodial sentence.

The Criminal Division of the Court of Appeal dismissed an appeal and certified the following point of law of general public importance:

“Does a trial judge have a discretion to refuse to allow evidence—being evidence other than evidence of admission—to be given in any circumstances in which such evidence is relevant and of more than minimal probative value?”

The House of Lords (sitting as the final court of appeal) granted leave and heard argument.

Legal Issues Presented

1. Whether a trial judge possesses, in any circumstances, a discretion to exclude prosecution evidence that is relevant and has more than minimal probative value.
2. Specifically, whether such a discretion extends to excluding evidence of a crime said to have been instigated by an agent provocateur (i.e., whether the alleged “entrapment” can operate indirectly through evidential exclusion).

Arguments of the Parties

Appellant’s Arguments

• Although English law recognises no substantive defence of entrapment, the trial judge should nonetheless have exercised a discretionary power to exclude evidence that was “unfairly obtained,” i.e., procured through police-instigated inducement.
• A number of earlier dicta and one decision (Reg. v. Payne) were cited as authority for a wide judicial discretion to exclude unfairly obtained evidence.
• If the judge had embarked upon a “trial within a trial” and found the facts of inducement proved, he should have refused to allow the Crown to prove its case, securing an acquittal.

Respondent’s Arguments

• Entrapment is not a defence; therefore exclusion of evidence on that basis would amount to creating a defence contrary to established law.
• The only recognised discretion is to exclude evidence whose prejudicial effect outweighs its probative value, or to protect the accused from self-incrimination in the narrow sense of post-offence admissions.
• Extending the discretion as urged would improperly enable judges to usurp prosecutorial decisions and undermine the public interest in convicting the guilty.

Table of Precedents Cited

Court’s Reasoning and Analysis

Delivering the principal opinion, Judge Diplock framed the certified question as requiring clarification of the exact circumstances, if any, in which a judge may exclude relevant, probative evidence other than admissions.

Key analytical steps:

1. Entrapment not a defence. Since counselling or procuring a crime is itself an offence, inducement by police or informer does not negate the principal offender’s guilt. To exclude evidence on this ground would be tantamount to creating a discretionary defence.
2. Distinction between source and use of evidence. The judge’s duty is to secure a fair trial, not to discipline the police. The fairness inquiry focuses on the evidential impact at trial, not on how the evidence was obtained.
3. Historical limits of discretion. Earlier cases recognise two discrete situations for exclusion: (a) where probative value is outweighed by prejudicial effect, particularly with “similar fact” or bad-character evidence; and (b) where evidence tantamount to a self-incriminatory admission is procured from the accused by threats, promises or trickery, invoking the maxim nemo debet prodere se ipsum.
4. Misreading of broad dicta. Obiter statements in Kuruma, Callis, and other cases suggesting a wider supervisory power were never applied to exclude evidence save in Payne, which fell within the confession analogy.
5. Policy considerations. Allowing judges to exclude evidence because of disapproval of police methods would undermine the conviction of the guilty and improperly overlap with civil remedies or disciplinary proceedings against officers.
6. Certified question answered. A general discretion exists only to refuse evidence if its prejudicial effect exceeds its probative value; otherwise, relevant admissible evidence must be received. Activities of an agent provocateur do not trigger the discretion.

Holding and Implications

HOLDING: APPEAL DISMISSED.

Implications: The House of Lords definitively confined the trial judge’s discretion to exclude prosecution evidence to two narrow categories: (1) where admissible evidence is likely to be more prejudicial than probative, and (2) where post-offence evidence amounting to an admission is unfairly procured from the accused. Evidence obtained through entrapment or other police misconduct remains admissible, and prior first-instance authorities (Reg. v. Ameer & Lucas and related cases) were overruled. The decision clarifies that disciplining investigative excesses lies outside the criminal trial and affirms the primacy of relevance in admissibility.