In Chell v Tarmac Cement and Lime Limited (Tarmac), the High Court considered Tarmac’s liability for an employee’s practical joke that went wrong. Mr Chell, who suffered serious injury because of the prank, brought a claim against Tarmac for negligence, claiming that Tarmac was vicariously and directly liable for the employee’s conduct.


Employers can be liable for damage or injury caused by employees if it occurs “in the course of the employee’s employment”. 

Employees’ conduct can include deliberate wrongdoing by an employee – for example, in a notorious case decided in 2018 (Bellman v Northampton Recruitment Limited) an employer was liable for an employee’s serious injuries when he was assaulted by the company’s Managing Director at an impromptu drinks party. 

However, in WM Morrison Supermarkets plc v Various Claimants, a landmark case held earlier this year, the Supreme Court decided that Morrisons supermarket was not responsible for harm caused by a rogue employee who leaked his colleagues’ personal information, including bank details, onto the dark web.


Mr Chell was a sub-contractor at Tarmac. During the period that Mr Chell was stationed at Tarmac’s site, Mr Chell alleged that there had been tensions between the sub-contractors and those who were employed by Tarmac, including an employee named Mr Heath.

On one occasion during the working day, Mr Heath exploded ‘pellet targets’ next to Mr Chell’s ear, which caused Mr Chell to suffer from a perforated eardrum, hearing loss and tinnitus. Tarmac consequently dismissed Mr Heath.

Mr Chell issued a claim for Tarmac’s negligence, alleging that Tarmac owed him a direct duty of care - which had been breached - and that Tarmac was vicariously and directly liable for Mr Heath’s actions. Mr Chell argued that, as Tarmac knew about Mr Chell’s concerns, it should have considered removing Mr Heath from the site, or separating the employees and sub-contractors. Mr Chell also alleged that Tarmac failed to provide appropriate supervision or to provide training to prevent horseplay.

Tarmac defended the claim on the basis that it was not responsible for the “horseplay” of Mr Heath; horseplay did not fall within “the course of Mr Heath’s employment” (see Background).

Decision at first instance

The County Court found that Tarmac were neither vicariously nor directly liable, taking into account that:

  • the pellet gun target was not work equipment but brought onto site by Mr Heath;
  • using pellet guns formed no part of Mr Heath usual duties, not least hitting them with a hammer;
  • hitting a pellet gun target with the hammer as a practical joke did not advance Tarmac’s goals; and
  • that Mr Chell and Mr Heath were on Tarmac’s premises at the same time only provided the opportunity for the practical joke rather than the practical joke being within the employee’s usual field of activities.

Therefore, in light of those findings the County Court dismissed Mr Chell’s action. Mr Chell appealed.

High Court’s Decision

The High Court had little difficulty in rejecting the suggestion that Tarmac was responsible for the consequences of Mr Chell’s prank.  Although the Court accepted that the Tarmac had been made aware of tensions between Mr Chell and his victim, there was no foreseeable risk of injury.

The Court said that there cannot be any expectation on Tarmac to formulate a health and safety policy or any other policy or procedure that, as the Court put it, “descends” to the level of preventing practical jokes or horseplay. Increased supervision to prevent horseplay, ill-discipline or malice was therefore not a reasonable steps to expect Tarmac to have identified and taken.

Furthermore, there was no sense in which Mr Heath’s actions were undertaken as part of his employment or furthering the purpose of Tarmac’s business. The workplace simply formed the backdrop for a practical joke, which had gone seriously wrong.

The High Court was scathing in its criticism of Mr Heath.  In its judgment, the High Court said that the practical joke: “….must be the lowest form of humour. It is seldom funny, it is often a form of bullying and it has the capacity, as in the present case, to go seriously wrong.”


The case is reassuring for employers to a certain extent, as it follows the line of reasoning in the Morrison’s decision that employer will not always be liable for the actions of employees who ‘go rogue’.  However, cases involving employer liability of employees’ actions are fact sensitive and, had the circumstances been slightly different, then the Court may have come to a different conclusion.

It is, therefore, sensible to ensure that staff are aware of their obligation to uphold high standards of behaviour generally, and particularly in respect of health and safety obligations.  Action should be taken if an employer becomes aware of tensions at work that may result in harm to others.  This judgment is particularly timely as we approach the Christmas work party season, when festivities may increase the risk that standards of behaviour towards colleagues might slip.  Whilst celebrations may be more subdued this year, given the current situation, employees should nonetheless be reminded to conduct themselves properly towards their colleagues, whether at work or at work-related social events. 

This publication is intended for general guidance and represents our understanding of the relevant law and practice as at October 2020. Specific advice should be sought for specific cases. For more information see our terms & conditions.

Date published

30 October 2020

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