Born in Marlow, Buckinghamshire, Hammond began playing drums aged 12, and joined his first band, The Farm, after winning a competition in the Melody Maker music newspaper.

[1] When Atomic Rooster drummer Carl Palmer left the group to form Emerson, Lake & Palmer in the summer of 1970, he was replaced briefly by Ric Parnell before Hammond was recruited as a permanent replacement in August, joining vocalist / guitarist John Cann and keyboard player Vincent Crane.

The band subsequently recorded the Death Walks Behind You album in September of that year, followed by the hit singles "Tomorrow Night" and "Devil's Answer".

Hammond and Cann joined forces with singer Al Shaw and bass guitarist John Gustafson to form Daemon, later changing the name to Bullet, and then Hard Stuff.

Hammond later joined The Intellektuals, an art punk band from London, led by Jack Hues and Nick Feldman.