The Supreme Court has handed down a judgment in Hayes v Willoughby 1 that redefines the scope of the most commonly used defence to claims of harassment.

The Claimant was the owner of several companies, one of which the Defendant had previously worked for. On termination of his employment the Defendant launched into a smear campaign against the Claimant, part of which involved allegations that the Claimant had stolen large sums of money from his companies. The Defendant sought to rely on the fact that he was pursuing a course of harassment in order to prevent or detect crime under section 1(3)(a) of the Protection from Harassment Act 1997 (the Act).

The Act prohibits conduct which amounts to harassment or which the perpetrator knows or ought to know amounts to harassment. However an allegation of harassment may be refuted if the conduct complained of was for the purpose of preventing or detecting crime.

In assessing the purpose of a perpetrator's activity the Supreme Court held that the test to be applied was not whether the person engaged in the activity reasonably believed their activity was for the purpose of preventing and detecting crime but whether this belief was held rationally. The reasonableness test was rejected on the basis that where the Act envisaged a reasonableness test to be appropriate it was stated expressly (see section 1 (1)(b) and 1 (3)(c)). The appeal was therefore dismissed because even though the Defendant honestly believed that the Claimant had stolen money from his companies this belief had been formulated through an irrational thought process.

The concept of rationality imports a minimum objective standard into the Act, meaning that a decision must not be judged to be illogical, arbitrary, capricious or outrageous. The move away from a subjective to an objective test should be heeded by those engaged in investigatory occupations, especially journalists, who in the course of their work might engage in conduct that could satisfy the definition of harassment under the Act.