I had always thought that the existence of post-traumatic amnesia, characterised by gaps in the patient's memory of events after an accident, particularly if the remaining “snapshots” of memory were particularly vivid, meant that the patient must have been knocked out, albeit briefly. I had always rejected the concept that fear, acute anxiety, panic, that which the layman calls “shock”, could be responsible for the phenomena of post-traumatic amnesia. That is until about 6 months ago.

I was driving in the wet, too fast, in a convoy in the outside lane. The conditions were appalling; I was alert. Six or seven cars in front of me were involved in a “front to rear shunt”, precipitated by a car that had been stuck on the inside lane …