(b) that is of a kind that persons generally are not authorised
to exercise without specific statutory authority.
(3) For the purposes of any
such proceedings, any act or omission involving an exercise of, or failure to
exercise, a special statutory power does not give rise to civil liability
unless the act or omission was in the circumstances so unreasonable that no
authority having the special statutory power in question could properly
consider the act or omission to be a reasonable exercise of, or failure to
exercise, its power.