I have just gone into the back of someone who had stopped in the middle of the road for no apparent reason as i was turning left at a set of lights. I slammed on my brakes but it was wet and i skidded into the back of him. There is no apparent damage to my car but there is to his. Am I at fault even though he had stopped for no reason? I have said I am not accepting liability ad he stopped in the middle of the road