This Latin phrase refers to the presumption in law that a child is incapable of forming the criminal intent to commit an offence.

Until its abolition in English law by section 34 Crime and Disorder Act 1998, it operated as a defence based on the presumption that a child under 14 years old was incapable of committing a crime. This presumption could be rebutted for children between the ages of 10 and 14 if the prosecution could satisfy the court that the child knew that what he was doing was seriously wrong, not “merely naughty or mischievous”. Children under 10 were deemed incapable in any event.

Following its abolition, the defence remains relevant only in relation to historic crimes which may have been committed before 1998.