"The most recent English authority on pranks at work ..."

This is one of those hard cases which fortunately seem to have made good law.

"A horrific incident occurred on 11^th June 2009 at the defendants' bodywork repair shop in Graveley, Cambridgeshire when a friend and co-employee of Mr Paul Graham used a cigarette lighter in the vicinity of Mr Graham, whose overalls had been sprinkled with a highly inflammable thinning agent called "Gunwash". As a result the overalls went up in flames; the fire started around Mr Graham's midriff, moved quickly up to his shoulders and caused Mr Graham very considerable injury. ...  The judge recorded the defendants' assertion that the incident was "horseplay" but that, the judge said, was a "gross underestimate" of Mr Wilkinson's actions which were better described as "a serious assault on his then friend". The judge categorised Mr Wilkinson's actions as deliberate and "clearly reckless" about the risks he created." So: is the employer liable?

The answer is of course no. To get there, however, the Court of Appeal referred to some other unfortunate cases of employee relations. Look out for:

- the care home employee who interrupted a drunken domestic to cycle to the care home and launch an unprovoked attack (employer not liable)

- the worker in a factory who "threw" his colleague "12 feet across the factory floor onto a table" (employer liable)

- "an employee, who supervised the defendant's health and safety policy, pulled Ms Wilson's ponytail making a ribald remark while he did so. This was little more than a prank but Ms Wilson sustained some injury. The Inner House held that the supervisor's actions were not connected with his employment; in pulling Ms Wilson's ponytail he was not doing anything in relation to his health and safety duties. The acts of the supervisor were a mere frolic for which the employee was not vicariously liable." (That's health and safety for you.)

- someone who pushed a wash basin against a Ms Aldred in order to startle her. "She turned round quickly to see what was going on and injured her back in the process" (employer not liable)

- and the awful case of Mr Romasov. "Mr Romasov was killed by a fellow employee (Mr McCulloch) in a Sainsbury's supermarket in Aberdeen; this fellow employee had, two days earlier, told Mr Romasov that he did not like immigrants and that he should go back to his own country. On the night of the killing there had been an argument when the co-employee objected to Mr Romasov sharing his table and a further argument in the toilets. Later the co-employee picked up a kitchen knife from the kitchenware section of the supermarket and stabbed Mr Romasov in one of the aisles." (employer not liable)

There have been quite a few temptations to let a hard case make bad law here, but the Courts seem to have resisted it.