In 1969, Powell answered a Melody Maker classified in which Martin Turner and Steve Upton advertised for a guitar player.

Being unable to choose between Powell and another applicant (Ted Turner), Wishbone Ash was formed with two lead guitarists.

Powell has recorded numerous sessions for other artists, including George Harrison, Ringo Starr, Kashif, Cilla Black, Stewart Copeland and Renaissance.

In 1988, Powell contributed to Miles Copeland III's Night of the Guitar project alongside Ted Turner, touring extensively with artists such as Randy California, Jan Akkerman, Steve Howe, Steve Hunter, Robby Krieger, Leslie West and Alvin Lee.

[4][5] In 2016 he released his autobiography, entitled Eyes Wide Open: True Tales of a Wishbone Ash Warrior.