Kevin, if an owner can't control their pet to stop it being offensive to other people then they have no business owning that pet. If you let your cat out of your garden, you are explicitly giving it permission to shit in other people's gardens and dig up their plants (never mind the health risks of kids playing in gardens full of cat shit). That means you may as well go and shit in the garden yourself, you've got that level of responsibility. The cat doesn't know any better, but the cat owner bloody well should.

I really want to find who owns the cat which shits on our garden. If I do, they'll have every cat shit I find deposited on their doorstep. I think that's the best solution - make the owners realise how antisocial they're being, and maybe they'll come up with a solution themselves, ie. keep the cat inside. It's certainly more humane than the non-lethal option I'm very tempted to resort to, which is lying in wait with a powerful catapult loaded with clods of earth.

Short-term, just keep watch for the cats and throw things at them - we have a rubber ball kept near the back door to throw at them. You don't have to hit them, you just have to scare them. They may learn that they can only come in during certain times when you're out, but at least they'll stay out of the garden for the rest of the time, and that cuts down on the amount of cat shit you have to clear up. Just be sure to never let a cat come into the garden unchallenged, or they'll think you're allowing them to be there.

Graham.