Improperly Obtained Evidence and Exclusion
Improperly obtained evidence and exclusion
This domain tests whether evidence obtained by illegality, breach of procedure or unfairness may still be used. The starting point is that relevance governs admissibility; impropriety does not automatically exclude. The court balances probative value against the fairness of using the evidence.
Core rules
- No automatic exclusion. Evidence obtained by unlawful search, seizure or arrest is not automatically inadmissible. The court considers the nature and gravity of the impropriety, its effect on the evidence, and the fairness of the trial.
- Criminal discretion. A judge may exclude prosecution evidence where its admission would have such an adverse effect on the fairness of the proceedings that it ought not to be admitted. This is broader than the prejudice discretion but is not a remedy for every breach.
- Fair trial, not fair investigation. The focus is on fairness of the proceedings, not the propriety of the police investigation. Bad faith is relevant but not decisive; good faith does not cure serious unfairness.
- Abuse of process. In extreme cases, proceedings may be stayed where the accused cannot receive a fair trial or where it would be offensive to justice to proceed.
- Civil cases. Illegally obtained evidence is generally admissible, subject to privilege, discretion and the court's control of proceedings.
Worked example
Police search D's home without a warrant and find a stolen laptop. The search is unlawful. The laptop is relevant and reliable, and its admission may not make the trial unfair, so the court may admit it. If the police deliberately violated the law to manufacture evidence, or if the defence cannot challenge its integrity, exclusion becomes more likely. The key is not the label 'illegal' but the effect on fairness.
Traps
Do not apply an automatic 'fruit of the poisonous tree' rule. Do not assume bad faith always excludes or good faith always admits. Do not confuse the fairness of the trial with the fairness of the investigation. Do not overlook abuse of process as a separate remedy.
Character, Similar Fact and Opinion Evidence
Character, similar fact and opinion evidence
This domain tests evidence about a person's disposition, evidence of other misconduct, and evidence of opinion. The unifying question is whether the evidence has sufficient probative force to justify the prejudice and distraction it may cause.
Core rules
- Good character. In criminal cases, evidence of the accused's good character may support credibility and, where relevant, propensity. The available direction depends on whether the character evidence is general or specific.
- Bad character. Evidence of misconduct or disposition is admissible only through defined gateways, such as agreement of all parties, the evidence being adduced by the accused, important explanatory evidence, or relevance to a matter in issue between prosecution and defence. Propensity and credibility are the usual routes; the court retains a discretion to exclude.
- Similar fact evidence. Evidence of other acts is admissible where its probative force, often through striking similarity, system or a unique signature, outweighs its prejudicial effect. Mere propensity is not enough.
- Opinion. Lay opinion is admissible where it is helpful and based on personal perception. Expert opinion is admissible where the witness has specialised knowledge, the evidence is reliable and helpful, and it is within the witness's expertise. Experts should not usurp the jury's function.
Worked example
D is charged with arson. The prosecution proves that D set two earlier fires using the same unusual ignition device and left the same signature. The evidence is similar fact evidence: the combination of system and unique signature gives it high probative force on identity and intent, which may outweigh prejudice. By contrast, evidence that D is 'a firebug' is mere propensity and inadmissible without a gateway. An expert who says 'D is guilty' has usurped the jury; an expert who explains the ignition device is giving admissible opinion.
Traps
Do not treat bad character as automatically admissible. Do not confuse similar fact with general propensity. Do not let an expert give a personal opinion on ultimate guilt. Do not ignore the discretion to exclude even where a gateway is satisfied.