Dennis Coslett (12 September 1939 – 20 May 2004) was a Welsh political activist, best known as a member of the Free Wales Army, who became notorious in 1969. Born in Carmarthen, Coslett was conscripted at the age of 18. He served as an infantryman with the Royal Welch Fusiliers and later became a merchant seaman. On his return to Wales, Coslett worked as a shot-firer in many of the small private coal mines in west Wales. Coslett lost the use of his left eye in an accident underground, and subsequently lost his job.