I tried to explain to different salespeople what I wanted: A slipcover to hide the footboard. Four people couldn't understand what I was looking for and stared at me like as if I was an alien. Then I went to Laura Ashley and explained again what I wanted and a smart lady told me that what I needed was a valance.
Ahhhh, valance, Magnolia, what you need is a valance, an ornamental drapery hung across a top edge, as of a bed, table, or canopy. Laura Ashley doesn't sell valances anymore but now that I knew the name, life was much easier. I googled again and discovered that Marks & Spencer and even John Lewis (one of the shops I went to) have it!
According to Wikipedia, a valance or bed skirt is a piece of decorative fabric that is placed between the mattress and the box spring of a bed. The purpose of a bed skirt is to give a stylish appearance to a bed without exposing the sides of the box spring or any space under the bed that may be used for storage. Historically, bed skirts were used to block draughts, which could chill the undersides of beds.
Valances are useful if you want to add some romantic style to your bedroom. It is like icing on a cake, not necessary but gives a final touch to it. It hides feet board and storage under your bed - and reduces the amount of dust that can accumulate under it. If you want to make a valance yourself, I have found a very simple design which provides a clean and modern look.
Image sources via my Pinterest board: Bed skirts or valances