Feral cat

We have a lot of cats visit our courtyard and those who mistake the gravel for cat litter are not particularly welcome. I am not specially a cat person but this particular one has something about it.  It makes occasional nonchalant forays into the house and looks at me with something between interest and distain.  It is quite nervous and runs away if I approach it.  I have softened towards it and have put out the odd saucer of milk to make friends.  It now allows me to get closer and has once miaowed an appreciation!