1. Detaining a person under section is a last resort and can only happen if there are no other ways to ensure their safety.
2. Section 3 (2) of the Mental Health Act 1983 states the conditions under which a person may be detained under section: he must be mentally disordered and he must pose a danger to himself or others.
3. Both conditions must be met: if a person is mentally disordered but not dangerous, he should be at liberty.
4. As soon as one of those conditions ceases to exist, he should be discharged.