B. (A Minor) v. Director of Public Prosecutions
1 All E.R. 833 (2000)

  • B was a 15 year-old who attempted to coerce a 13 year-old into sex. He was arrested and charged with inciting a child to commit an act of gross indecency.
  • At Trial, B argued that he had honestly believed the girl was over 14. The Trial Judge ruled that a mistake of fact could not constitute a defense.
    • The Judge relied on Regina v. Prince (L.R. 2 Cr. Cas. Res. 154 (1875)).
  • B pled guilty and then appealed.
  • The British House of Lords reversed the Trial Judge and allowed the appeal.
    • The House of Lords found that is necessary for the prosecution to prove the absence of a genuine belief on the part of the defendant, which did not have to be on reasonable grounds, that the victim was 14 or over.
    • The House of Lords found that mens rea is an essential ingredient unless Parliament has indicated a contrary intention either expressly or by necessary implication.