Per Lord Sumption in Crawford Adjusters & Ors v Sagicor General Insurance (Cayman) Ltd & Anor (Cayman Islands )  UKPC 17 at para 133-134:
Malice is as a general rule irrelevant to liability in tort. The principle was finally established by the decision of the House of Lords in Bradford Corpn v Pickles  AC 587. It was restated by Lord Watson in Allen v Flood  AC 1, 92, in terms which have been adopted or paraphrased by judges and writers ever since that case was decided:
Although the rule may be otherwise with regard to crimes, the law of England does not, according to my apprehension, take into account motive as constituting an element of civil wrong. Any invasion of the civil rights of another person is in itself a legal wrong, carrying with it liability to repair its necessary or natural consequences, in so far as these are injurious to the person whose right is infringed, whether the motive which prompted it be good, bad, or indifferent. But the existence of a bad motive, in the case of an act which is not in itself illegal, will not convert that act into a civil wrong for which reparation is due. A wrongful act, done knowingly and with a view to its injurious consequences, may, in the sense of law, be malicious; but such malice derives its essential character from the circumstance that the act done constitutes a violation of the law.
There are two significant exceptions to this principle. The first is the tort of conspiracy to injure, where the existence of a dominant intention to injure the plaintiff may make actionable conduct which would otherwise be lawful. This has generally been regarded as sui generis, and is usually justified by reference to the especially pernicious effect of combinations. The second exception comprises a limited category of causes of action in which the essence of the tort is the abuse of a public function for some collateral private purposes of the person performing it. This may be (and generally is) established by proof of targeted malice. The paradigm case is the tort of misfeasance in public office, which in its modern form dates back to the decision in Ashby v White (1704) 14 St Tr 695 . The tort may be committed by any person performing a public function notwithstanding that he is not actually employed in the public service: Henly v Lyme Corporation (1828) 5 Bing 91, 107-108. As Lord Steyn put it in Three Rivers District Council v Governor and Company of the Bank of England (No 3)  2 AC 1, 190, malice is a condition of liability notwithstanding the general rule that it is irrelevant in the law of tort, because "the rationale of the tort is that in a legal system based on the rule of law, executive or administrative power 'may be exercised only for the public good' and not for ulterior and improper purposes."