There was absolutely nothing I could do. It was on a 40mph road and it just jumped out in front of me. I tried my best to help it but it's died. I feel absolutely terrible. I've just about managed to calm myself down enough to write this and call the police who are on their way.
It isn't collared so I imagine the police are going to have to take it to a vet to check for a chip. Tried knocking on what properties I have and no luck.