Bull Denim is a traditional name for a simple undyed twill fabric, perhaps named for John (or formerly Johnny) Bull, the archetypal Englishman first depicted by John Arbuthnot in 1712.

This interpretation of a bull denim is woven on an ecru cotton warp with a mixed weft of Yorkshire-grown hemp and wool.The wool fibre is spun into the hemp to provide elasticity to the yarn, and this weft is woven to the face of the fabric, leaving a smooth cotton inside to the garment, with a textured outside.The cloth is woven in a left hand twill, making it particularly soft and comfortable to wear.