Diamond Head was one of the leaders of the "New Wave Of British Heavy Metal" back in the 1970's.  They never achieved the level of fame that Judas Priest and Iron Maiden did, but they were a very important part of the movement, mostly because they were an influence on Metallica, who turned out to be one of the biggest Metal bands of all time.

Diamond Head suffered similar fates to many bands from that era.  Brian Tatler was the founding member but there seemed to be a lot of people coming and going which hurt the band's consistency.  They also experimented with their sound a bit too and never really hit gold with radio.  Despite all this Diamond Head has trudged forward and have continued playing before massive audiences.

Metallica