Fosse, a warehouse owner, claimed damages for negligence against Condé Nast (the first tenant) and Phoenix (the second tenant) relating to a fire that had destroyed its warehouse. Condé Nast had rented part of the warehouse that Fosse also occupied. Phoenix was an employment agency that employed four workers who had been seconded to work for Condé Nast at the warehouse. Those four workers plus a security guard had been the only people on site at the time the fire broke out.

Expert forensic evidence could not identify which of five possible causes had started the fire. The possible causes were: a discarded cigarette by Fosse’s employees; a discarded cigarette by the agency workers; an electrical fault; arson by an intruder who gained access whilst Fosse’s employees remained on the premises; or arson by an intruder who gained access after Fosse’s employees left. Fosse issued proceedings, claiming that the fire had been caused by a cigarette carelessly discarded by one of the agency workers, alternatively by an intruder who gained access by the agency workers’ negligence in leaving a door open.

The judge noted that the evidence did not allow him to form a view as to the probable cause of the fire. He was, however, able to form the view that it was probably not caused by a carelessly discarded cigarette by one of the four agency workers. It was simply not possible, on the balance of probabilities, to determine that the fire was caused by either of the two remaining feasible causes. As a result, Fosse had failed to prove its case on a balance of probabilities.