A thoroughly interesting set of replies and certainly thought provoking. From reading countless incident and accident reports of over-runs over many years it has been my personal view only that from 15 knots below V1 it is safer to continue the take off if on a limiting runway length wet or dry surface. I know this would horrify the experts but it is a question of learning from the experience of others. Fortunately I have never had to put this to practice except in the simulator.