That's an idea, but the flap is in the most out of the way place imaginable and I am getting so ancient I can't really reach it to put the bin there. Because it's so awkward the controls for the flap are actually outside the house and not inside it. Unless anybody can suggest an extra strong four way flap my plan is to get my drill out and fit some kind of swivel type doorstop on the outside of the flap, so they can clamber over it to get in the house when it's in position but they won't be able to push their way out. I've never had this problem before. I suspect it's Bertie, he's such a big strong cat.