A prince of Britain who, according to Geoffrey of Monmouth, was a descendant of Brutus.

He was the son of King Gorboduc (Gorbodug) and Queen Judon (Iudon) and had an older brother, Porrex. The two brothers quarreled over the right of succession to the English throne, and Porrex plotted to ambush Ferrex, who fled to Gaul. He returned with an army, was defeated and killed.

Porrex ruled in the sixth or fifth century BC.