In Mohamud v WM Morrison Supermarkets plc [2016] UKSC 11, the Supreme Court had to decide whether the employer was vicariously liable for a violent attack made on a customer by one of its employees. It examined whether there was a close enough connection between the assault and the nature of the employee’s role so that it would be just and reasonable to hold the employer vicariously liable.


Mr Khan was an employee of Morrison Supermarkets plc, working in the kiosk serving customers at a Morrisons petrol station on its premises at Small Heath, Birmingham. The claimant, Mr Mohamud, was of Somali origin and was a customer who had entered the petrol station to ask if he could print some documents from a USB stick.

Mr Khan responded using expletives, stating that Mr Mohamud could not print the files at the petrol station. When Mr Mohamud objected to Mr Khan’s use of expletives, Mr Khan told him to leave the premises, using threatening and abusive language. Mr Khan then followed Mr Mohamud out to his car, opened the passenger door and proceeded to assault Mr Mohamud, punching him and kicking him to the ground. In carrying out the assault, Mr Khan ignored instructions from his supervisor, who tried to intervene.

Mr Mohamud brought a claim for personal injury against Morrisons and the question arose as to whether or not the Company could be held vicariously liable for Mr Khan’s unprovoked and violent attack.


The doctrine of vicarious liability provides that an employer will be held liable for civil wrongs committed by an employee where a connection between the employer and the primary wrongdoer can be established and the connection between the employment and the wrongful conduct is sufficiently close to make it fair and just to hold the employer legally responsible for the wrongdoer’s act.

Establishing vicarious liability is therefore a two stage test. The present case turned on the interpretation of the second limb of the test, also known as the “close connection” or “sufficient connection” test. This test comes from the case of Lister v Helsey Hall [2001] UKHL 22, which has since been confirmed in a number of decisions. The test is in itself open to interpretation because it inevitably comes down to a value judgement based on the particular circumstances in any given case as to whether an employee’s wrongful conduct is sufficiently connected to their employment.

The courts have tended to take a broad approach to vicarious liability, particularly in response to cases that have raised the issue of employer culpability in sexual assault and child abuse. The principal example is the Christian Brothers case in which the defendant, an international association which provided children with a Christian education, was held vicariously liable for the sexual abuse of children by members of the institute (known as brothers) who taught at an approved school.

County Court decision

The trial judge was unable to conclude that the Company was vicariously liable for the acts of Mr Khan. When assessing the second limb of the test for vicarious liability and applying the “close connection test” from Lister, the judge could not find that there was a sufficient connection between Mr Khan’s employment and his conduct. It was conceded that Mr Khan’s job did involve some interaction with customers, serving them and helping them, but this was not found to be sufficiently closely connected to the unprovoked assault for the Company to be held vicariously liable.

A further factor central to the trial judge’s decision was that Mr Khan had done a positive act by leaving the kiosk and following Mr Mohamud onto the forecourt, acting outside the instructions given to him by his employer.

Court of Appeal decision

Mr Mohamud appealed the first instance decision but the Court of Appeal upheld the decision. The reasoning was along similar lines to the first instance decision but went further by saying that, because Mr Khan’s duties did not involve a clear likelihood of confrontation, mere interaction with customers in his role was not enough to make his employer vicariously liable for his violent conduct.

Supreme Court decision

Mr Mohamud appealed to the Supreme Court and asked for the “sufficient connection” test to be replaced by a “representative capacity” test. The test proposed was wider, asking whether a reasonable observer would consider that the employee in question was acting in the capacity of a representative of the employer at the time the tort was committed. The focus would not be on the closeness of the connection between the work the employee was employed to do and the tortious conduct but would relate to the setting the employer had created. Mr Mohamud argued that the “representative capacity” test was fulfilled as Mr Khan, an employee tasked with dealing with customers at the petrol station, was the human representative of the employer and the employer had created the setting by placing Mr Khan in close physical contact with Mr Mohamud.

The Supreme Court rejected the “representative capacity” test, regarding it as unnecessary because it did not substantively differ from the Lister test. The judges preferred the broad approach to the “close connection” test whereby Mr Khan’s violent act was sufficiently closely connected to his employment for Morrisons to be vicariously liable. In particular, one of the judges refuted that Mr Khan leaving the kiosk to follow Mr Mohamud to his car broke the connection, stating that it would not be right to regard Mr Khan as having “metaphorically taken off his uniform the moment he stepped from behind the counter”. The Supreme Court therefore upheld the claim and held that Morrisons was vicariously liable for Mr Khan's actions.


Holding an employer vicariously liable for the illegal acts of its employees is not a new development. Indeed, the doctrine has expanded through case law particularly in relation to sensitive issues such as sexual assault and child abuse. Nevertheless, this decision is noteworthy principally because it is difficult to see what more the employer could have done to distance itself from the harm caused by its employee.

Even the most prudent employers are aware that whether or not an employee decides to go "on a frolic of their own” is not something that can be easily controlled. Previous case law tended to reflect this. It appears that the Supreme Court in this case was motivated largely by public policy considerations and arguably this has the effect of widening the already broad approach taken to the “close connection” test. This raises the question: is the “close connection” between an employee who commits a tort and his employment now too close for comfort?

The Mohamud v WM Morrison decision was handed down on the same day (and by the same judges) as another decision in relation to vicarious liability: Cox v Ministry of Justice [2016] UKSC 10. The Cox case considered the first limb of the test to establish vicarious liability, relating to the nature of the relationship between the employer and the employee. In this case the Supreme Court took the view that an employment relationship could be imposed between the Ministry of Justice and a prisoner who negligently caused injury to a prison employee. It seems, therefore, that the Supreme Court is prepared to extend vicarious liability beyond the traditional employment relationship. Interestingly, Lord Reed commented that there now exists a “modern theory of vicarious liability” and that the doctrine is “on the move”, which potentially leaves scope for it to become even broader in future. 

This article is for general information only and reflects the position at the date of publication. It does not constitute legal advice.