Principles and procedures to admit and exclude evidence - Bu...

Learning Outcomes

This article examines burden and standard of proof and their role in admitting and excluding evidence, including:

• The distinction between the legal (persuasive) burden and the evidential burden, and how each is allocated across offences and defences in criminal proceedings
• The required standards of proof in criminal and civil contexts—“beyond reasonable doubt” versus “balance of probabilities”—and the practical effect of the modern “being sure” jury direction
• The operation of reverse or modified burdens at statute or common law—such as insanity, diminished responsibility, and key statutory exceptions—and their compatibility with the presumption of innocence under Article 6 ECHR
• The interaction between burdens, standards, and admissibility or exclusion of evidence, including evidential sufficiency, adverse inferences, voir dire hearings, and submissions of no case to answer (with reference to R v Galbraith)
• The allocation of burden and standard in commonly examined defences—self-defence, loss of control, intoxication, duress, mistake, automatism, and necessity—and how these affect trial strategy
• The procedural roles of judge, jury, and magistrates in determining questions of law and fact, managing formal admissions, and applying the correct standard of proof
• The application of these principles to SQE1-style problem questions and scenarios, enabling accurate issue-spotting, structured analysis, and exam-relevant conclusions

SQE1 Syllabus

For SQE1, you are required to understand the burden and standard of proof and their impact on admitting and excluding evidence, with a focus on the following syllabus points:

• The core principle that the prosecution bears the legal burden of proof in all criminal cases and must prove guilt beyond reasonable doubt.
• The differences between legal burden and evidential burden, including which party carries each, and the circumstances where the defendant must bear either.
• Operation of the evidential burden: what constitutes making a defence or fact “live,” and the resulting effect on the prosecution’s burden.
• The distinction in standard of proof in criminal and civil cases, including when the standard shifts to “balance of probabilities.”
• Circumstances when the defence bears the legal burden (reverse burden), and the standard they must meet (e.g., insanity, diminished responsibility).
• The compatibility of reverse burdens with Article 6(2) ECHR and the presumption of innocence; interpretative approaches by courts.
• The procedural and substantive impact of these principles on the admissibility and evaluation of criminal evidence.
• The allocation of burden/standard in key defences (e.g., self-defence, loss of control, duress, mistake, insanity, diminished responsibility).
• The application of worked examples/scenarios, and the practical effect these rules have in court.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. Who bears the legal burden of proof in a criminal trial, and what is the required standard?
2. What is the evidential burden, and how does it differ from the legal burden?
3. In which circumstances might the defendant bear the legal burden of proof, and what standard applies?
4. What is meant by "beyond reasonable doubt" and "balance of probabilities"?

Introduction

The concepts of burden and standard of proof are central to the fairness and structure of criminal trials. They establish not only which party must prove disputed issues, but also to what level of certainty. The allocation and operation of these burdens underpin the fundamental presumption of innocence and govern the admissibility and weight of evidence. Understanding how the legal and evidential burdens interact with the required standard, and how reverse burdens operate in conjunction with statutory defences or exceptions, is essential for analysing criminal cases.

Key Term: legal burden
The obligation on a party (typically the prosecution in criminal cases) to prove the elements of a fact in issue—including any matters alleging guilt— to the required standard in law. Also referred to as the "persuasive burden" because the party must ultimately persuade the court or jury of its case.

Key Term: evidential burden
The obligation to adduce, point to, or produce sufficient evidence for a particular fact or defence, so that the issue can be rightly considered by the judge or jury. Unlike the legal burden, this is not a requirement to prove the fact, but merely to supply enough credible evidence to make it a live issue in the proceedings.

The Burden of Proof

The allocation of the burden of proof in criminal proceedings is governed by both common law principles and statutory provisions. In general, the overarching presumption is that of the presumption of innocence. This is enshrined in the common law (extending back to Woolmington v DPP [1935] AC 462) and in Article 6(2) ECHR, requiring the prosecution to bear the legal burden of proof of all elements of the offence—including, where necessary, disproving any defences that may be raised.

Key Term: presumption of innocence
The foundational principle that every person accused of a crime is presumed innocent until proven guilty according to law. This presumption operates to require the prosecution to bear the burden of proof, subject to narrow exceptions, and any doubt must be resolved in favour of the accused.

The Legal Burden in Criminal Cases

The legal burden of proof is the responsibility to establish, to the satisfaction of the tribunal of fact (jury or magistrates), the facts necessary to maintain or defeat a charge or defence. In criminal cases, this typically means the prosecution must prove:

• The actus reus (prohibited conduct or consequence)
• The mens rea (required fault element)
• The absence of any legal justification or excuse, once the issue is “live”

The practical effect is that, unless the law specifically provides otherwise, it is never for the defence to prove their own innocence; it is for the prosecution to prove guilt, even where the defendant puts forward a positive defence such as self-defence or alibi.

Occasionally, statutes reverse this position and place the legal (persuasive) burden directly on the defendant (see “reverse burdens” below). In these rare circumstances, the standard of proof required of the defendant is lower.

The Evidential Burden

For most defences, the defendant need only discharge an evidential burden to set up a defence at trial. If the defendant adduces some credible evidence (from their own testimony, cross-examination, or calling of witnesses) to make a defence a live issue, the judge must leave it to the tribunal of fact. It is then for the prosecution to disprove the defence to the applicable criminal standard.

The evidential burden may also rest on the prosecution in respect of all facts in issue—if, at the conclusion of the prosecution case, there is insufficient evidence on an essential element, the court will uphold a submission of no case to answer (see R v Galbraith [1981] 1 WLR 1039).

Key distinctions between legal and evidential burden:

• The legal burden is decisive: it determines who must prove an issue and what the outcome will be if proof is not forthcoming.
• The evidential burden is activating: it ensures an issue is properly raised, but does not require final proof.

Key Term: standard of proof
The threshold of certainty to which a fact must be established before the decision-maker may act on it. In criminal cases, this is typically “beyond reasonable doubt” for the prosecution and “on the balance of probabilities” (more likely than not) for most defence burdens.

The Standard of Proof

Criminal Standard: Beyond Reasonable Doubt (“so that you are sure”)

The prosecution’s legal burden must be proven to the criminal standard. Judges now often direct juries using the phrase "You must be sure" rather than "beyond a reasonable doubt" to clarify the required level of certainty. This reflects the strong presumption in favour of the accused: the risk of error, unless proof is compelling, must fall on the prosecution.

Key Term: beyond reasonable doubt
The standard of proof in all criminal trials for prosecution burdens. It means that the tribunal of fact must be certain (sure) of the defendant’s guilt before convicting. If they are left with a reasonable doubt by the totality of the evidence, the only proper verdict is acquittal.

There is no requirement for mathematical certainty. The standard is not so high as to exclude all hypothetical possibilities, but it does demand a high degree of certainty, more than mere probability.

Civil Standard: Balance of Probabilities

Where the legal burden is placed upon the defendant (for example, in insanity or diminished responsibility), the standard of proof is the civil standard—the “balance of probabilities.”

Key Term: balance of probabilities
This standard is met if it is more likely than not (i.e., greater than 50% likelihood) that the fact in issue is true. It is the standard used in civil cases, and it applies to defences in criminal trials where the defendant bears the legal burden.

Comparing the Standards

• For prosecution: beyond reasonable doubt (or “so that you are sure”)
• For defence: balance of probabilities (where the legal burden is reversed); no standard attaches to the evidential burden, as it only requires making an issue live

Who Decides?

• Questions of law (including admissibility of evidence) are for the judge (in Crown Court) or magistrates (in the magistrates’ court).
• Questions of fact (including whether the standard of proof is met) are for the jury or magistrates.
• Where the evidential burden is not discharged by either party, the judge may direct an acquittal or not allow the issue to be considered.

Reverse Burdens and Shifting the Burden of Proof

Reverse Burdens

A “reverse burden” refers to the situation in which the legal burden (persuasive burden) is placed by law upon the defendant. Examples include:

• Insanity: Where a defendant pleads insanity, the legal and evidential burden is on the defence to prove the elements of insanity, on the balance of probabilities (M’Naghten rules).
• Diminished responsibility: For murder, defendants must prove this partial defence (s.2 Homicide Act 1957) on the balance of probabilities; it is not for the prosecution to disprove (see also R v Lambert [2002]).
• Statutory defences: Some statutes expressly or impliedly require the defendant to prove elements of certain defences. For example:
  • S.5(2) Misuse of Drugs Act 1971 (defence of lack of knowledge of the presence of drugs)
  • Motoring offences (e.g., drink-driving), where defendants must prove certain matters, such as lack of knowledge or lawful authority.

Key Term: reverse burden
Any statutory or common law requirement placing the legal (persuasive) burden on the defendant for a particular issue, typically requiring proof on the balance of probabilities.

Evidential Burden Shifts

In most defences, the defendant is only required to produce enough evidence to raise the issue (the evidential burden): for example, self-defence, automatism, duress, necessity, or mistake.

Once the evidential burden has been satisfied, the legal burden reverts to the prosecution to disprove the defence beyond reasonable doubt.

Key Term: burden of proof
The general phrase for obligations to either prove (legal burden) or merely raise (evidential burden) a particular fact or defence.

Worked Example 1.1

Scenario:
Sophie is charged with possession of a controlled drug with intent to supply. She claims the drugs were for personal use.

Question:
Who bears the burden of proof, and what standard applies?

Answer:
The prosecution must prove, beyond reasonable doubt, that Sophie possessed a controlled drug with intent to supply. If Sophie adduces credible evidence that the drugs were for her own use (even her own statement at trial is sufficient), this raises the defence. The evidential burden thus shifts to Sophie, but once she raises the issue, the prosecution must disprove her account and prove intent to supply beyond reasonable doubt.

Worked Example 1.2

Scenario:
David is charged with murder but raises the defence of diminished responsibility.

Question:
Who bears the burden of proof for diminished responsibility, and what standard applies?

Answer:
In this case, diminished responsibility is a partial defence to murder under s.2 Homicide Act 1957. David bears the legal and evidential burden to prove, on the balance of probabilities, that he was operating under a recognised medical condition which substantially impaired his responsibility for the killing. The prosecution retains the burden to prove the remaining elements of murder beyond reasonable doubt.

Reverse Burdens and Human Rights

Assigning a legal burden to a defendant engages the right to be presumed innocent under Article 6(2) of the ECHR. Such reverse burdens are interpreted restrictively, and courts will only uphold them if justified by sufficient public policy goals and the burden relates to facts “peculiarly within the knowledge” of the accused. The courts—where possible—will construe the statutory provision as imposing only an evidential burden on the defence, unless the wording and context require otherwise (see R v Lambert [2002]; R v Sheldrake [2005]).

Worked Example 1.3

Scenario:
Lucy is charged with possession of an offensive weapon in a public place. She claims lawful authority.

Question:
Who has the burden of proof regarding lawful authority, and to what standard?

Answer:
The prosecution must prove that Lucy was in possession of an offensive weapon in a public place. Lucy bears the legal burden to prove, on the balance of probabilities, that she had lawful authority or a reasonable excuse for possession, as required by the Prevention of Crime Act 1953.

Worked Example 1.4

Scenario:
Rashid is charged with murder and raises the defence of loss of control.

Question:
Who must prove loss of control, and to what standard?

Answer:
Rashid has an evidential burden to raise sufficient evidence of loss of control (s.54 Coroners and Justice Act 2009). Once raised, the prosecution has the legal burden, and must disprove the defence beyond reasonable doubt. Rashid is not required to prove the defence.

The Role of Burden and Standard of Proof in Admitting and Excluding Evidence

Admissibility and Case Management

Allocation of the burden and standard of proof is significant to the admissibility, scope, and weight attached to evidence. The following points are essential:

• The prosecution must present evidence on each element of the offence; if not, the case may be dismissed at the close of their case, commonly via a submission of no case to answer (see R v Galbraith).
• The judge determines questions of law, including admissibility. Where the admissibility of evidence (e.g., confessions, bad character, hearsay) is contested, it is decided at a voir dire in the Crown Court, or by the magistrates in summary proceedings.
• Disputed facts, such as whether a confession is reliable or the defence of insanity applies, are resolved by the relevant standard of proof.

Formal Admissions

Either party may make a formal admission of a fact under s. 10 Criminal Justice Act 1967. Once a fact is formally admitted, it does not require further proof at trial.

Weight of Evidence and the Decision-Maker

The fact-finder (jury or magistrates) assesses the credibility and weight of live, documentary, and circumstantial evidence. Where the evidence is in doubt or unreliable, it may fail to satisfy the relevant standard, and the accused is entitled to acquittal.

Adverse Inferences

Modern criminal procedure allows for adverse inferences to be drawn from silence in interview or trial, but only in line with strict statutory requirements (Criminal Justice and Public Order Act 1994, ss. 34–37). Silence cannot alone supply proof of guilt, but may supplement the evidence where the defendant fails to account for facts later relied upon.

Evidential Sufficiency and Submissions of No Case to Answer

If the prosecution fails to adduce sufficient evidence on the elements of an offence, the court will direct an acquittal: this is a submission of no case to answer. The evidential burden is therefore significant—it must be satisfied for the legal burden to ever come into play.

Illustrative Application in Trial Procedure

At trial, each burden is activated at various procedural stages:

• Prosecution opening: legal and evidential burden to be discharged.
• Defence case: if a positive defence is raised, evidential burden is to be met by adducing some evidence. If the law places the legal burden on the defence, both burdens must be satisfied.
• The judge may rule submissions of no case to answer or exclude unreliable/confession evidence depending on how the burdens are met.

Worked Example 1.5

Scenario:
A defendant is tried for affray. The prosecution adduces evidence of presence at the scene but nothing linking the defendant to the violence.

Question:
Can the case proceed?

Answer:
If there is insufficient evidence that the defendant participated in violence or threatened violence, the judge must uphold a submission of no case to answer. The prosecution has failed to discharge the evidential burden.

Worked Example 1.6

Scenario:
A defendant is charged with theft, and claims he believed he had the owner’s consent.

Question:
Is the belief a defence, and who must prove what?

Answer:
In theft, the prosecution has the legal burden to prove dishonesty, including disproving a claim of honest belief in consent. The defendant need only raise an evidential burden—often through their own testimony — and the prosecution must negative this beyond reasonable doubt.

Summary Table

Key Point Checklist

This article has covered the following key knowledge points:

• The presumption of innocence requires the prosecution to prove guilt to the criminal standard throughout the trial, except where statute assigns a reverse burden.
• The legal burden refers to the obligation to prove particular facts or defences; the evidential burden is the duty to make an issue live.
• The criminal standard is “beyond reasonable doubt” (or “so that you are sure”) for the prosecution; the defence, when carrying a legal burden, meets the “balance of probabilities.”
• Statutes or common law may place a reverse burden on the defendant—e.g., insanity, diminished responsibility, certain statutory exceptions.
• The evidential burden for most defences is satisfied by “some evidence”; the prosecution must then disprove the defence to the criminal standard.
• When the legal burden is with the defence, the standard is the balance of probabilities, and the prosecution retains the burden on all other elements.
• All reverse burdens engage the presumption of innocence under Art. 6(2) ECHR and will be read restrictively unless Parliament’s intention is clear.
• The allocation of burden and standard of proof directly influences the way in which evidence is admitted, excluded, and evaluated—affecting the overall fairness and outcome of a trial.
• The operation of these doctrines is illustrated by the mechanisms of submissions of no case to answer, admissibility and exclusion rulings, and the drawing (or not) of adverse inferences.
• The defence must be alert to both legal and evidential burdens in managing case strategy, including calling evidence, cross-examination, and responding to prosecution proof.

Key Terms and Concepts

• legal burden
• evidential burden
• presumption of innocence
• standard of proof
• beyond reasonable doubt
• balance of probabilities
• reverse burden
• burden of proof