My car foot. (Sorry... American humour.)
Both Mrs Media and I have cars without boots (American "trunk"). In hers, it's some towels, a first aid kit, her spare tire (beneath the flooring), and some canvas shopping bags. In mine, a golf umbrella, some tools, a container of oil., a couple of towels, and a mesh net and a folding compartment-type box that can be used for grocery bags so they don't slide all over the place.