The defence of qualified privilege must be seen in its overall setting in the law of defamation. Historically the common law has set much store by protection of reputation. Publication of a statement adversely affecting a person's reputation is actionable. The plaintiff is not required to prove that the words are false. Nor, in the case of publication in a written or permanent form, is he required to prove he has been damaged.
Truth is a complete defence.
If the defendant proves the substantial truth of the words complained of, he thereby establishes the defence of justification. With the minor exception of proceedings to which the Rehabilitation of Offenders Act 1974 applies, this defence is of universal application in civil proceedings. It avails a defendant even if he was acting spitefully. The common law has long recognised the 'chilling' effect of this rigorous, reputation protective principle. There must be exceptions.