The Act, which was enacted in October 2007, was largely based on previous common law and sets down the framework for decision making. It is supported by a Code of Practice and imposes a duty on health-care professionals to follow that code.

The Code helpfully defines capacity, how it is assessed and how decisions should be made on behalf of those who lack capacity, whether temporarily or permanently, to ensure any steps taken are in the best interests of the individual.

The Act sets down the circumstances in which an individual maybe detained and treated for a mental health condition. It may only be used where it is required to protect the individual or others from serious harm.

Detention under the Act does not create an assumption of lack of capacity. Therefore, any treatment decisions that do not relate to the patient's mental health disorder requires their consent unless it can be demonstrated they lack the capacity to make that specific decision.