Mice

[Tarrel]

Get a cat. Seriously. The smell will deter the field mice from coming in, and the cat will go to work on the ones in the house. Go for a female. They are the expert mousers (just as female lions are the primary hunters in a pride).

On a more tongue-in-cheek note, you could always eat the cat if things get desperate. More meat on it than a mouse!

When we were letting out our cottage as a holiday let, we had endless problems with mice. Since we moved in permanently with our two cats, no bother.