MCA 2005 s1
1.—(1) The following principles apply for the purposes of this Act.
(2) A person must be assumed to have capacity unless it is established that he lacks capacity.
(3) A person is not to be treated as unable to make a decision unless all practicable steps to help him to do so have been taken without success.
(4) A person is not to be treated as unable to make a decision merely because he makes an unwise decision.
(5) An act done, or decision made, under this Act for or on behalf of a person who lacks capacity must be done, or made, in his best interests.
(6) Before the act is done, or the decision is made, regard must be had to whether the purpose for which it is needed can be as effectively achieved in a way that is less restrictive of the person's rights and freedom of action.
The Mental Capacity Act 2005 has been fully in force since 1 October 2007. For details of proposed amendments, see Mental Health Act 2007.