Yesterday I had already reversed half way out of my parking bay when I noticed the car behind but down one bay had put their car also into reverse as there lights had come on but as I was already out but needed to do a half turn so that I would touch the parked car that was next to me I went forward before reversing again. This is when I noticed the other drives had started to pull of their bay so I hit my horn to warn them & get them to stop but they still carried on and hit on car. I couldn't move mine out of the way because of the angle I was at. Who would the insurance company would say is at fault? Would it be deemed as 50/50 as I have no witness.