Neighbour's cat pooing on my doorstep

[confusedperson]

We found cat's poo in our garden quite a few times, although it is annoying but as there are so many cats walking around freely, you can't do anything.
Lately we have been annoyed by somebody's cat pooing just in front of our door. It seems that it is doing this on purpose. Needless to say, that we absolutely hate this. I think I've identified the cat, but don't know which neighbour's cat it is. And, if I knew, I doubt if the neighbours would be in control of the cat.
Today I stepped in it and walked it all over my downstairs before noticing :( I have a baby and a toddler, and it is not only annoying, not safe too. I washed it away with hot water, but I am sure it will happen again.
How do I prevent this??

Some well placed cayenne pepper on your doormat and a water gun to wet the offender when he/she is anywhere near your property!

Or orange peel. This worked when our cat started peeing in the living room corner for some strange reason.

Are you sure its cats.
Foxes do this on my front and back door step

Are you sure it's not a hedgehog?

Will be keeping an eye on this thread as suffer from the same problem - neighbourhood over run with cats who like using my front garden as a toilet. The day I woke up and found crap on my doormat I was nearly sick. Have replaced doormat and now spray it with 'Get Away Spray' - a spray repellent that I bought from B&Q. Time will tell if it works.

foxes do it to mark territory, in very prominent positions. Fox much is very black.

You can get a repellent spray from garden centres and DIY sheds or petshops, but you need to clean away all traces of the muck and smell first as it will encourage them to return. I usually spray with general purpose household cleaner, but I understand bio washing powder in hot water is very effective.

Foxes and cats are nervous of large male carnivores, so if you can get a few men to wee on the doorstep after a big roast dinner, that will also act as a repellent.

Ha ha at the PigletJonh's post, last sentence :)
I will look for the repellents next week.
It does not happen everyday, so I am not sure if it is matter of coming back by the smell.
But I am pretty sure it is a cat. I think I even know which cat. This morning I found very fresh crap and saw the cat starring at me from the pavement [yuck].
Will also get some repellent to chase slugs away from my living room....

[dreaming of selling up my Victorian house and moving into newish built house]