He held the WBC World Featherweight title in 1968. He compiled a career record of 61-6.
He was a wildly successful amateur, and won the Amateur Boxing Association bantamweight title in 1958, as well as a gold medal at that year's Commonwealth Games.
Following his career he was voted the greatest citizen in his hometown of Merthyr Tydfil, Wales.
His brother, Glyn Winstone, owned a boxing-themed cafe.
He failed multiple times to take the world title from Vicente Saldivar, but finally took it when Saldivar retired.
