B (A Minor) v DPP [2000] 2 AC 428

A 15‑year‑old boy incited a 13‑year‑old girl to perform oral sex, honestly believing she was over 14. The House of Lords held that the offence under section 1(1) of the Indecency with Children Act 1960 requires mens rea as to age; an honest belief, even if unreasonable, is a defence.

Facts

On 19 August 1997 a 13‑year‑old girl was a passenger on a bus in Harrow. The appellant, then aged 15, sat next to her and several times asked her to perform oral sex on him. She repeatedly refused. He was charged with inciting a girl under 14 to commit an act of gross indecency contrary to section 1(1) of the Indecency with Children Act 1960.

At his trial in the Harrow Youth Court the appellant initially pleaded not guilty. The primary facts were admitted, including that he honestly believed the girl was over 14. There was no finding on whether this belief was reasonable. The justices were asked to rule whether that belief could be a defence. They held the offence was one of strict liability as to age. The appellant then changed his plea to guilty, was convicted, and received an 18‑month supervision order.

He appealed by way of case stated. The Divisional Court (Brooke LJ, Tucker and Rougier JJ) dismissed the appeal, holding that section 1(1) created a strict liability offence as to the child’s age. The House of Lords heard a further appeal.

Issues

Primary issue

Whether, on the correct interpretation of section 1(1) of the Indecency with Children Act 1960, a defendant is entitled to be acquitted of the offence of inciting a child under 14 to commit an act of gross indecency if he holds, or may hold, an honest belief that the child was aged 14 or over.

Supplementary issues

• If such a belief can be a defence, must it be held on reasonable grounds?
• On whom does the burden of proof lie in relation to that belief?

Judgment

Common law presumption of mens rea

The House reaffirmed the strong common law presumption that, where a statutory offence is silent as to mental element, Parliament is presumed to require mens rea unless it has clearly excluded it.

Lord Nicholls summarised the effect of the presumption, citing Lord Reid in Sweet v. Parsley:

. . . there has for centuries been a presumption that Parliament did not intend to make criminals of persons who were in no way blameworthy in what they did. That means that whenever a section is silent as to mens rea there is a presumption that, in order to give effect to the will of Parliament, we must read in words appropriate to require mens rea. . . . it is firmly established by a host of authorities that mens rea is an essential ingredient of every offence unless some reason can be found for holding that that is not necessary.

Lord Steyn linked this presumption to the wider constitutional “principle of legality”, quoting Lord Hoffmann in Ex p Simms:

But the principle of legality means that Parliament must squarely confront what it is doing and accept the political cost. Fundamental rights cannot be overridden by general or ambiguous words. This is because there is too great a risk that the full implications of their unqualified meaning may have passed unnoticed in the democratic process. In the absence of express language or necessary implication to the contrary, the courts therefore presume that even the most general words were intended to be subject to the basic rights of the individual.

Lord Hutton restated the same principle, citing Lord Goddard CJ in Brend v. Wood and the Privy Council in Gammon, emphasising that mens rea is excluded only by clear or necessary implication.

Construction of section 1(1) of the 1960 Act

Section 1(1) criminalises any act of gross indecency with or towards a child under 14, or inciting such a child to such an act. The provision is silent as to the defendant’s state of mind regarding age. The House considered whether, by necessary implication, Parliament intended strict liability as to age.

Lord Nicholls stressed that the offence is serious and widely drawn; it can cover behaviour ranging from serious predatory paedophile conduct to relatively innocuous sexual experimentation between teenagers, with significant penal and stigma consequences. These factors strengthened the presumption in favour of a mental element.

He observed that an age ingredient is in principle no different from any other element of an offence. If a defendant genuinely believes the other person is 14 or over, he does not intend to commit an act of gross indecency with a child under 14. Unless the statute displaces the presumption, that intention forms part of the offence.

Lord Steyn agreed that, focusing on the wording of section 1(1), the breadth of the actus reus and the seriousness of the offence meant the presumption of mens rea was prima facie applicable. He noted that the subsection extends to verbal sexual overtures between teenagers and that criminalising such conduct as a strict liability offence would be “far reaching and controversial”.

Effect of the Sexual Offences Act 1956

The Crown argued that section 1(1) of the 1960 Act formed an “appendix” to the Sexual Offences Act 1956, which it said embodied a legislative policy of strict liability in age‑based sexual offences, relying in particular on:

• Reg v Prince (abduction of a girl under 16);
• R v Forde and R v Maughan (indecent assault on girls or boys under 16 under sections 14 and 15 of the 1956 Act);
• express defences based on mistake in certain 1956 Act provisions (for example, the “young man’s defence” in section 6(3), and provisions concerning defectives).

Lord Nicholls and Lord Steyn rejected this submission. They accepted that the 1960 Act was an appendix to the 1956 Act and that there was a broad policy of protecting young children, but emphasised the origin and structure of the 1956 Act: it was a “motley” or “rag‑bag” collection of offences from diverse periods, lacking a coherent or consistent scheme on mental elements.

Lord Steyn noted that the express inclusion of knowledge or mistake defences in some provisions of the 1956 Act did not, of itself, justify inferring strict liability where a provision was silent, quoting Lord Reid’s warning in Sweet v Parsley that such drafting could not displace the presumption.

The House also treated sections 14 and 15 as materially different comparators. Those sections criminalise indecent assaults, where an assault (necessarily involving intentional conduct) is an ingredient and indecent assault has long been a crime. Section 1(1) by contrast creates a new, broader offence in which the age element is essential; absent age, the conduct is not criminal. This difference did not justify displacing the presumption.

Rejection of Prince as a controlling principle

The Crown sought to rely on Reg v Prince as establishing a special rule that mistake as to age is no defence in age‑based sexual offences. The House declined to treat Prince as laying down a controlling principle for modern law.

Lord Steyn analysed Blackburn J’s reasoning, founded on drafting defects in the 1861 Act which no longer exist, and Bramwell B’s moralistic approach, concluding that Prince was “a relic from an age dead and gone” and inconsistent with the modern requirement that a defendant be judged on the facts as he believed them to be.

Lord Nicholls stated that some reasoning in Prince was “at variance” with the modern presumption regarding mens rea and must, to that extent, be regarded as unsound, though the correctness of the actual decisions in Prince and Maughan was not in issue.

Honest belief versus reasonable belief

The House held that the traditional formulation of the presumption, requiring an honest and reasonable belief in exculpatory facts, no longer reflected modern criminal law. Lord Nicholls traced a development in case law, including:

• DPP v Morgan (rape);
• R v Kimber (indecent assault);
• R v Williams (Gladstone) (assault/self‑defence);
• Beckford v R (self‑defence in murder);
• Blackburn v Bowering (contempt/assault on court officers).

These authorities emphasised that it is the defendant’s actual, subjective belief which matters. The unreasonableness of that belief may be powerful evidence that it was not truly held, but, if genuinely held, its reasonableness is irrelevant to guilt.

Lord Nicholls concluded that Lord Diplock’s formulation in Sweet v Parsley must be read “as though the reference to reasonable grounds were omitted”. Lord Steyn described a “general shift from objectivism to subjectivism” and held that it would be inconsistent with this development to require reasonable grounds as part of a belief defence under section 1(1).

Practical and evidential concerns

The Crown argued that recognising a belief‑based defence would unduly hamper enforcement and make convictions more difficult. The Law Lords rejected this as a reason to override the principle. They cited Sir Owen Dixon’s warning in Thomas v The King against excluding inquiry into states of mind because of mistrust of juries.

Lord Steyn pointed out that the Crown would only have to disprove an honest belief where there was some evidential basis for it, and that recklessness or indifference as to age would suffice for guilt.

Allocation of the burden of proof

On the burden of proof, the House applied the “golden thread” described in Woolmington v DPP. Lord Steyn quoted Viscount Sankey LC’s formulation and held there was no basis for placing a legal burden on the defendant.

Lord Hutton stated that once the defendant had raised some evidence that he honestly believed the child was over fourteen, the burden of proof lay on the Crown to disprove that belief.

Outcome

All members of the Appellate Committee agreed that section 1(1) requires mens rea as to the age element. A defendant is entitled to acquittal if he held, or may have held, an honest belief that the child was 14 or over; that belief need not be reasonable. The prosecution bears the burden of proving the absence of such a belief.

Lord Irvine LC, Lord Mackay, Lord Nicholls, Lord Steyn and Lord Hutton each stated that the appeal should be allowed. Lord Steyn expressly said he would “allow the appeal and quash the conviction”; Lord Hutton and others concurred in allowing the appeal.

Implications

This decision confirms that the general presumption of mens rea applies fully to age elements in serious sexual offences unless clearly displaced by statute. Section 1(1) of the Indecency with Children Act 1960 is not an offence of strict liability as to age.

The House re‑aligned the presumption with modern subjective principles of criminal responsibility: a genuinely held mistaken belief, however unreasonable, can negate the required mens rea, with reasonableness relevant only to whether the belief was in fact held. It also weakened the authority of older strict‑liability reasoning in Prince‑type cases.

While acknowledging that this approach may make some prosecutions more difficult and could reduce the protective effect of section 1(1), the House held that it was for Parliament, not the courts, to depart from the presumption and to do so in clear terms. The judgment thus has significant constitutional and doctrinal importance in reaffirming the principle of legality and the centrality of mens rea in serious statutory crimes.

Verdict: Appeal allowed; the conviction was quashed. Section 1(1) of the Indecency with Children Act 1960 requires proof that the defendant did not honestly believe the child was 14 or over; an honest belief, even if unreasonable, is a defence, and the burden lies on the prosecution.

Source: B (A Minor) v DPP [2000] 2 AC 428