Traps. Lots of them, with regularly changed bait and positioning. The longer a mouse survives, the cleverer the swine becomes. You have to get them early and be ruthless. Wherever there is pooh, stick a trap. Poison can be used too, but it won't work on its own. Head squashing traps are your infantry: they will retake and secure your territory from the vermin menace. And once they've gone, keep the traps in position as a defensive line for future attacks. Revel in your kills like a latter day Hemingway. Keep a tab, mark them up on your fridge door.