but how would you know it had no owner ?
In fact, I dont think it matters if the cat is stray or not. There was a thread on here somewhere a few months ago. Some lad was worried, as on one of his permissions, a cat had come through the hedge, and one of his lurchers had it. The owner of the cat, then threatened him with legal action. Someone looked it up, but like I say, I'm not 100% sure, but they posted that, whenever a cat comes onto your property, it becomes your property. (Ill probably get a load of abuse from cat owners now!)
Feral cats can be controled as i understand it