ColinOldnCranky wrote:The situation was a wet road with all parties doing the right thing but someone had dumped a bin of KFC refuse over the road in the early hours of the morning which a resident had then replaced in the bin. Tyres and all were fine. Speeds were fine. Your belief "point" that I was at fault was not the case. Even the other driver had no issue with our shared misfortune.
Colin, that's an extenuating circumstance.
As always, these things are decided on both the law and the facts. Prima facie you are at fault if you rear end a vehicle as you are assumed not to have been keeping an adequate braking distance or not paying attention and it is the responsibility of the following driver to do those things. However, if you were keeping an adequate braking distance for the known conditions and something unforeseeable such as grease on the road causes you to crash, that is an "out". You were not negligent.
If being cut off, and the act of being cut off directly causes you to collide with the car doing the cutting off, or prevents you avoiding the collision, that is another out.
However, hitting the back of the car that has been cut off is generally not, unless he cuts into your lane while trying to evade the collision and that causes you to hit him. However, if he is simply braking suddenly for whatever reason (eg, avoiding running over a cat or a child or another car) and you hit him from behind, that is not an "out" for you. He has not broken a rule to cause you to hit him.
In the situation of the OP, in the absence of any such extenuating facts provided, he would normally be regarded as at fault.