In English folklore, the Lambton Worm was a dragon-like serpent said to haunt the River Wear near County Durham.
The best-known version tells of John Lambton, who caught a strange worm while fishing in the River Wear. He threw it into a well, where it grew to enormous size. The creature later emerged, terrorized the surrounding countryside, and demanded milk or other offerings. John eventually returned from the Crusades and fought it, wearing armor and using a strategy that prevented the worm from reuniting its severed body.
The legend is usually associated with Lambton Castle and the village of Fatfield in County Durham. It belongs to the broader tradition of British “worms,” a word historically used for large serpents or dragon-like creatures, rather than referring to a small earthworm.
The story has many local variations, and details such as the exact battle site differ between accounts. It is sometimes grouped with Saint George legends, but the Lambton tale centers on a hereditary curse and a regional noble family.