Removing old cable that goes through external wall
I've removed several of these, but never from a brick wall. Typically the hole is a bit larger diameter than the wire and the gap is sealed on both sides with caulk or rubber grommets. If you remove the gap seal it should be trivial to pull it out. I would dig around the cable on the exterior side with a knife or pliers to free up the cable. On the interior side, you can see the rubber grommet so you can cut or pull that off.
You seem to have more cable on the interior so it would be easier to get a grip on that side, but if you'd rather pull from outside you can use vise grips to clamp the cable and a pry bar and a wood/brick fulcrum to pull a few centimeters until you have enough wire to get a good hand grip. Pulling the cable inside would be a shorter pull though, as it has just a few centimeters more than the 20cm wall thickness.