In the first of what we hope will be a regular column, Jon Day embarks on new adventures as Country Mouse, so named after the Aesop fable The Town Mouse & the Country Mouse. Our Town Mouse, Thomas Marks, will make his first appearance soon…

On the shelf above my desk I keep my small collection of found objects: a piece of razor-sharp flint; the tail of a squirrel; a rabbit’s skull, light and brittle as parchment. Pride of place is a malevolent aged jaw, six inches long, curved like a scimitar and spiked with several lethal-looking teeth. It is the jaw of a pike. It must have belonged to an enormous fish; certainly double figures, maybe a twenty or thirty pounder. I found it one spring morning on the banks of a lake in Oxfordshire, though how it got there I’ll never know. Who, or what, could have caught such a fish?