Claimants (or their relatives) had been passengers on international flights with the defendant carriers. In each case a DVT had resulted in serious injury or death. It was assumed that DVT was caused by the flight, defendants had known about the rsik of DVT and failed to warn of such rsik or advise passengers how to avoid or minimize it. The House of Lords unanimously found that, where a passenger suffered DVT on a flight during which nothing out of the ordinary had occurred, this did not amount to an accident capable of founding recovery under Article 17 of the Warsaw Convention as the term “accident” denoted an event or occurrence having a particular quality or characteristic. For the purposes of Article 17, it was the cause of the harm which constituted the accident, not the harm itself. These requirements ruled out Article 17 recovery in DVT cases where no more can be said than that the cramped seating arrangements in the aircraft were a causative link in the onset of the DVT. Not warning of the risk and not advising passengers of precautions which might be taken to minimize the risk were non-events which could not properly be described as accidents.