If a person ("D") does an act in connection with the care or treatment of another person ("P"), the act is one to which this section applies if—
before doing the act, D takes reasonable steps to establish whether P lacks capacity in relation to the matter in question, and
when doing the act, D reasonably believes—
that P lacks capacity in relation to the matter, and
that it will be in P's best interests for the act to be done.
D does not incur any liability in relation to the act that he would not have incurred if P—
had had capacity to consent in relation to the matter, and
had consented to D's doing the act.
Nothing in this section excludes a person's civil liability for loss or damage, or his criminal liability, resulting from his negligence in doing the act.
Nothing in this section affects the operation of sections 24 to 26 (advance decisions to refuse treatment).