Over a professional career that spanned thirty years he is best known as the bassist of British rock band Supertramp and for his musical association with Leo Sayer.

His first public appearances were with the Birmingham-based 1960s beat band "The Silverlinks" that he joined with his best friend and school mate Robert Shorter, who played drums, in 1964.

The follow-up single, a rock adaption written by Farrell and loosely based on the Peer Gynt "Hall of the Mountain King Overture", was never released but the twenty-minute-long stage version of the number would become a centerpiece of the band's show.

Aflalo joined the original London cast of Hair and Farrell became head road manager for American singing act Johnny Johnson and the Bandwagon during their seven-month tour of the UK.

[2] Following his departure from Supertramp, Farrell joined the British progressive rock band Fields, replacing departed bassist-vocalist Alan Barry.

In October 2007 former Supertramp guitarist Roger Hodgson paid tribute to Farrell by performing "Rosie Had Everything Planned" to a packed house at Birmingham Symphony Hall.

After his close association with Leo Sayer ended, Farrell continued to be involved in the music industry, writing songs, recording and playing as a session musician for TV shows and tours behind major artists, including spells with American guitarists Joe Jammer and Tim Buckley.