Heavy metal music
Critics disagree over who can be thought of as the first heavy metal band. Most credit either Led Zeppelin or Black Sabbath, with American commentators tending to favour Led Zeppelin and British commentators tending to favour Black Sabbath, though many give equal credit to both. A few commentators—mainly American—argue for other groups including Iron Butterfly, Steppenwolf or Blue Cheer. Deep Purple, the third band in what is sometimes considered the "unholy trinity" of heavy metal (Black Sabbath, Led Zeppelin, and Deep Purple), despite being slightly older than Black Sabbath and Led Zeppelin, fluctuated between many rock styles until late 1969 when they took a heavy metal direction.
Deep Machine
Deep Machine were a heavy metal band from the East London that first came into existence in 1979. Founded by lead guitarist Bob Hooker, the band’s music was influenced by other NWOBHM bands such as Iron Maiden and in particular, Judas Priest.