AIBU to declare all out war...?

[chaosmonkey]

The mouse that appeared in my food cupboard 3 days ago sat on top of the humane mouse-trap and did a big poo! (well, big for a mouse, obvs...)

WIBU to go and get poison for it...?

nope, go get that fucker.

Get a proper 'little nipper' mouse trap. Poison is a horrible way to die - internal bleeding which takes time. The little nipper is quick at least. You will need to put a snack on the unset trap a few times and then set it once the mouse is used to going to the trap for food. It's heartbreaking but one mouse very soon equals lots of them.

The little bastard is mocking you. Show no mercy.