(1)  This section applies to proceedings in respect of a claim to which this Part applies that are based on an alleged breach of a statutory duty by a public or other authority in connection with the exercise of or a failure to exercise a function of the authority.

(2)  For the purpose of any such proceedings in respect of a claim, an act or omission of the authority does not constitute a breach of statutory duty unless the act or omission was in the circumstances so unreasonable that no authority having the functions of the authority in question could properly consider the act or omission to be a reasonable exercise of its functions.

(3)  In the case of a function of a public or other authority to prohibit or regulate an activity, this section applies in addition to section 41 .