4.—(1) In determining for the purposes of this Act what is in a person's best interests, the person making the determination must not make it merely on the basis of-
(2) The person making the determination must consider all the relevant circumstances and, in particular, take the following steps.
(3) He must consider-
(4) He must, so far as reasonably practicable, permit and encourage the person to participate, or to improve his ability to participate, as fully as possible in any act done for him and any decision affecting him.
(5) Where the determination relates to life-sustaining treatment he must not, in considering whether the treatment is in the best interests of the person concerned, be motivated by a desire to bring about his death.
(6) He must consider, so far as is reasonably ascertainable-
(7) He must take into account, if it is practicable and appropriate to consult them, the views of-
as to what would be in the person's best interests and, in particular, as to the matters mentioned in subsection (6).
(8) The duties imposed by subsections (1) to (7) also apply in relation to the exercise of any powers which-
(9) In the case of an act done, or a decision made, by a person other than the court, there is sufficient compliance with this section if (having complied with the requirements of subsections (1) to (7)) he reasonably believes that what he does or decides is in the best interests of the person concerned.
(10) "Life-sustaining treatment" means treatment which in the view of a person providing health care for the person concerned is necessary to sustain life.
(11) "Relevant circumstances" are those-
The Mental Capacity Act 2005 has been fully in force since 1 October 2007. For details of proposed amendments, see Mental Health Act 2007.