Quinn v Leathem  AC 495
Conspiracy; inducing breach of contract; trade union
Leathem, a butcher, had employees who did not belong to the Belfast Butchers’ Association (BBA). After experiencing some difficulties, he asked for his employees to be admitted to the BBA. The BBA, for whom Quinn was the treasurer, put pressure on a customer not to buy Leathem’s meat and also called out one of his own employees.
Upon direction by the judge that they have to decide whether Quinn and his co-officers’ main motive was to injure Leathem’s interests, the jury found malicious conspiracy between Quinn and other BBA officers. The Irish Court of Appeal later affirmed their view. Quinn (alone) appealed. He argued that a violation of a legal right must be shown – a conduct that would have been actionable regardless of motive and whether conspiracy was present. In other words, he claimed that an act that is not in itself actionable will not be made actionable by the presence of a malicious motive.
Dismissing Quinn’s appeal, the Court held that his conspiracy to wrongfully and maliciously induce Leathem’s own employees and customers to stop working for/buying from him was actionable upon proof of damage. While people may come together lawfully (even if this may result in injury to the interests of others), if such a get-together is solely for the malicious purpose of causing harm to another, it becomes unlawful. Any kind of violation of someone’s legal rights (whether contractual, tortious or other) that was knowingly committed and offers no explanation/justification is actionable in tort.