Daniël Johannes Stephanus van der Bank v The State

The appellant was charged with rape and indecent assault of a 16 year-old girl during 1999. The complainant had suffered brain damage during pregnancy and at birth, and functioned at a mental level of approximately 8.5 years old despite being 16 years old at the time of the offences. She attended Sonnestraal School for moderately mentally challenged children. The appellant employed the complainant's mother and often fetched the complainant from school. He admitted to having sexual intercourse with the complainant on three occasions and inserting his finger into her vagina, but claimed it was consensual. The complainant testified through an intermediary despite being 19 years old at the time of trial (section 170A(1) of the Criminal Procedure Act at that time only permitted intermediaries for witnesses under 18). Expert evidence established the complainant operated at the mental level of an 8.5 year-old and was incapable of giving informed consent. The appellant was aware she attended a special school and was mentally challenged.

• Whether evidence given through an intermediary by a witness over 18 years old was admissible under section 170A(1) of the Criminal Procedure Act as it stood at the time
• Whether the complainant was capable of giving valid consent to sexual intercourse despite being 16 years old biologically
• Whether evidence excluding the complainant's testimony was sufficient to sustain the conviction
• What constitutes valid consent in common law rape

The appeal was dismissed. The convictions for rape and indecent assault were upheld. The sentence of 12 years' imprisonment (with four years conditionally suspended for five years) remained in force.

Valid consent to sexual intercourse requires that consent be given by someone capable of consenting. Where a complainant is intellectually challenged, their mental capacity must be expertly assessed to determine capability to consent. Where undisputed expert evidence establishes that a complainant functions at a mental age well below their biological age and is incapable of giving informed consent, any purported consent is invalid. An accused who knows or ought to know that a complainant is mentally challenged and incapable of giving consent cannot rely on a defense of consent. The mental capacity to consent, not biological age alone, is determinative in assessing whether valid consent was given in sexual offence cases.

The court noted that it was unnecessary to consider whether S v Dayimani 2006 (2) SACR 594 (E) was correctly decided regarding the admissibility of evidence through intermediaries for witnesses over 18 years old. The court observed that the full court did not have the power to consider an application for leave to appeal - only the Supreme Court of Appeal is empowered to do so in terms of section 16(1)(b) of the Superior Courts Act 10 of 2013. The court noted that section 170A was subsequently amended in 2007 by section 68 of Act 32 of 2007 to include not only witnesses who were biologically under the age of eighteen but also those who were regarded as mentally under the age of eighteen. The court commented on the balance between protecting child witnesses and an accused's right to a fair trial achieved by section 170A, which has been found to be constitutionally sound.

This case establishes important principles regarding consent in sexual offences involving mentally challenged complainants. It clarifies that mental capacity, not merely biological age, determines the ability to consent to sexual activity. The case demonstrates that where expert evidence establishes a complainant lacks the mental capacity to give informed consent, any purported consent is invalid regardless of the complainant's biological age. The judgment also addresses evidentiary issues regarding the use of intermediaries and demonstrates that where an accused admits the actus reus but claims consent, the State can prove guilt through expert evidence establishing incapacity to consent, even without relying on the complainant's direct testimony. The case reinforces the protection of vulnerable persons with intellectual disabilities from sexual exploitation.