It is a defence to the
publication of defamatory matter if the defendant proves that —
(a) the
matter carried, in addition to the defamatory imputations of which the
plaintiff complains, one or more other imputations ( contextual imputations )
that are substantially true; and
(b) the
defamatory imputations do not further harm the reputation of the plaintiff
because of the substantial truth of the contextual imputations.