William Llewellyn Dyer (11 September 1883 – 1936) was an English businessman and a professional footballer who played as a striker for Athletic Club.
[7] Dyer was a key element in this historic rivalry that served as one of the drivers of football as a mass phenomenon in Bilbao, since their duels aroused great expectation.
[16] Dyer created the Unión Ciclista Bilbaina, he was a sailor, a cricket and tennis player, he liked boxing and his business was also going very well with his shipments of iron and coal.
[4][17] In 1936, shortly after the start of the Spanish Civil War, Dyer died in San Juan de Luz, at the age of 53.
[3] His son Patrick (born in 1916) was responsible for the English espionage service MI-16 in the Biscayan capital for over 20 years, notably during World War II, controlling the port movement of the Germans and collaborating with the Basque nationalist groups after the fall of Bilbao.