“The law of vicarious liability is on the move“, began one of two judgments of the United Kingdom Supreme Court yesterday, both focusing on vicarious liability principles.
Cox v Ministry of Justice  UKSC 10 includes at  an explanation of the issues by Lord Reed:
The scope of vicarious liability depends upon the answers to two questions. First, what sort of relationship has to exist between an individual and a defendant before the defendant can be made vicariously liable in tort for the conduct of that individual? Secondly, in what manner does the conduct of that individual have to be related to that relationship, in order for vicarious liability to be imposed on the defendant? Although the answers to those questions are inter-connected, the present appeal is concerned with the first question, and approaches it principally in the light of the judgment in the Christian Brothers case, where the same issue was considered. The appeal in the case of Mohamud is concerned with the second question, and approaches it principally in the light of the historical development of this branch of the law…
In Cox the facts required the court to decide whether the prison service, a public authority, was vicariously liable for the act of a prisoner in the course of his work in a prison kitchen, where the act is negligent and causes injury to a member of the prison staff. The Court held that the authority was liable, referring back to the requirements laid down in the Christian Brothers case, which were met and saying at : The prison service carries on activities in furtherance of its aims. The fact that those aims are not commercially motivated, but serve the public interest, is no bar to the imposition of vicarious liability.
In Mohamud v W M Morrison Supermarkets PLC  UKSC 11, returned to the question of an employer’s vicarious liability in tort for an assault (on a customer) carried out by an employee. In carrying out the attack the employee ignored instructions from his supervisor, who came on the scene at some stage. At  –  Lord Toulson noted the need to consider two things – the field of activities entrusted to the employee, and whether there was a sufficient connection between the position and the wrongful conduct. Here the employee’s job was to attend to customers and respond to their enquiries, which he did in an abusive way before progressing to assault the customer. The court held that there was an unbroken sequence of events. There was no separate relationship between the employee and the customer. The conclusion appears at : …”it was an order to keep away from his employer’s premises, which he reinforced by violence. In giving such an order he was purporting to act about his employer’s business. It was a gross abuse of his position, but it was in connection with the business in which he was employed to serve customers. His employers entrusted him with that position and it is just that as between them and the claimant, they should be held responsible for their employee’s abuse of it.”