It's a difficult one as our neighbour does exactly the same with her cats. They are always hungry and begging for food for all my neighbours and us. Somebody reported her to the RSPCA as her dog was in a state, they sorted that out but said as the cats 'looked' healthy, they couldn't (more like wouldn't) do anything!

The RSPCA Inspector even hinted to me that as the cats weren't microchipped that the cats could 'go missing' and end up in a nice rescue shelter somewhere!