One of my neighbour's kitten was a visitor to my garden last summer and was tolerated by my cats too. Have you checked with neighbours?
If the cat looks well fed and happy then more than likely he or she does have a home and is pushing its luck visiting the neibouring dwellings

If you are concerned check for a chip as Speadie said.
I have taken in strays in the past. One was a very skinny female that my ex husband found hanging around a building site and the second was a very ill mature man who I gave a home to for his final days. I managed to get him to a vet and he was very poorly with feline aids and did not survive for much longer after I took him in.
_________________Still the official cheeky one
