In reply to Trangia:
> The problem is that an injured animal won't let you touch it.
Cycling home one night some years ago, I saw a cat that had obviously had its back broken. It was obviously terrified, and I couldn't get near it (and I'm generally very good with cats).
I rang the RSPCA (as suggested above), and got the telephonic equivalent of a shrug.
I'm still ashamed that I didn't go back and try to do something for the poor thing, but I simply couldn't see how I would be able to collect it, and my attempts would force it painfully to try to escape, rather than crawl quietly to die somewhere, as cats often do.
A year or so ago, I came home to see a large ginger tom, apparently sleeping at the side of my house. Since it was one I'd never managed to get near, I expected it to run off. But of course, it didn't; stiff and cold with a small trickle of blood from its mouth. No collar, so I had to put it in the dustbin to keep it from attracting other predators, and dreaded having to leave it out for the binmen the next night. Fortunately, I got home the next evening to find a 'have you see Rufus?' leaflet, so I was able to extract him from the bin, and take him home. Since I'm very empathetic (some might say pathetic..), I was barely able to speak when I handed him to the woman who answered the door, and rushed off in tears. She left a card the next day thanking me for giving them the chance to say goodbye to him.