The London Borough of Southwark v KA

Capacity to consent to sexual relations requires a practical and non-paternalistic assessment of whether the person understands the sexual nature and mechanics of the act, that it may cause pregnancy, and that it may cause ill-health. The understanding required is rudimentary and concerns salient information, not every detail. Understanding contraception, the mechanics or duration of pregnancy, immigration requirements, or financial-remedy law is not ordinarily required.

The person must understand that they have a choice whether to consent. Capacity to marry requires a broad understanding of the marriage contract and its usual duties and responsibilities, and capacity for sexual relations. Welfare concerns and the perceived wisdom of a proposed marriage are distinct from capacity under the Mental Capacity Act 2005.

The local authority sought declarations concerning KA, a 29-year-old man with a learning disability. It was concerned that he might be married without capacity to consent, following information that his family had explored a marriage which would provide him with future support.

KA lived with his family and received support. A consultant psychologist assessed him and concluded that he lacked capacity for sexual relations and marriage. At the final hearing she was cross-examined. The court accepted her factual and clinical evidence, while deciding the legal question of capacity for itself.

The issues included KA’s capacity to litigate, to make care and welfare decisions, to consent to sexual relations, and to marry. The central questions concerned the information relevant to sexual relations and marriage, and the proper separation of capacity from welfare.

1. Declarations made. KA lacked capacity to conduct the proceedings. The statutory presumption of capacity was not displaced in relation to sexual relations, marriage, care and welfare, or medical treatment in general.

2. Under the Mental Capacity Act 2005, the court had to assess capacity on the balance of probabilities by applying the diagnostic and functional tests. The relevant information comprises salient matters, not every peripheral detail. The court had to consider all the evidence and not expert evidence alone.

3. For sexual relations, the core information is the mechanics and sexual character of the act, that it can lead to pregnancy, and that it can create health risks. KA understood each matter to the necessary rudimentary level. Pregnancy is a foreseeable consequence of heterosexual relations and is separate from ill-health. His mistaken belief that pregnancy would always occur, and his lack of understanding of its mechanics and duration, did not establish incapacity.

4. Understanding methods of contraception, or the particular nature and seriousness of sexually transmitted illness, was not required. Those matters went too far into welfare and practical detail. KA understood and retained that sexual activity could lead to illness.

5. The ability to understand the concept and necessity of one’s own consent is fundamental to capacity: the person must know that they have a choice and can refuse. The court did not need to decide whether understanding a partner’s consent was independently fundamental, since KA understood the need for consent by both parties.

6. Capacity to marry is status-specific, not person-specific. It requires a broad understanding of the nature of marriage and its usual duties and responsibilities, including its financial consequences and the spouses’ special legal and personal connection. It also requires capacity for sexual relations. KA met that test. His lack of detailed understanding of entry clearance and financial-remedy procedure was irrelevant, as were welfare concerns about whether marriage would be wise or successful.

not stated in the judgment.