At least five bands/artists have been called Nucleus. 1. Nucleus were a pioneering jazz-rock band from the U.K., who continued in different incarnations from 1969 to 1985. In their first year they won first prize at the Montreux Jazz Festival, released their first album (Elastic Rock), and performed both at the Newport Jazz Festival and the Village Gate jazz club. They were led by Ian Carr, who had been in The Don Rendell & Ian Carr Quintet during the mid and late 1960s, and was a respected figure in British jazz for more than forty years.