How did the cat get inside the wall in the first place?Is it your cat? Depending on the cat, shaking treats near where they entered (or any other opening near them) usually works. Or try scratching the skirting board (like a mouse trying to make a hole) near a hole the cat can get out from. You can leave food/treats/toys, and water near any entrances/exits or holes the cat got in from, and it's just a waiting game. If the cat got into the wall easily, it should come out easily when it's hungry.

Worst case is if the cat is stuck or is completely trapped, then you will have no choice but to smash a hole in the wall, retrieve the cat, then repair the hole. Good luck! Citation : I've had 90 cats and dogs since then 50s, fostered 2000 cats and kittens