Sullivan, real name James Tomkins, was a highly-accomplished musician who started his career in 1959 as a member of Marty Wilde's band.
He helped future Deep Purple icon Ritchie Blackmore learn to play guitar and also started Yes and Asia guitarist Steve Howe on his road to success. He recorded tracks for 55 number one hits, starting with Frankie Vaughn's "Tower Of Strength" in 1960 and ending with Pilot's "January" in 1975.
In between times he worked with George Harrison, Frank Zappa, Alvin Stardust, The New Seekers, Thunderclap Newman, Angel, Love Affair, Long John Baldry, Marmalade, The Tremeloes, Jet Harris and Tony Meeha plus many others.
He also appeared in two of the UK's biggest-ever novelty hits: Rolf Harris' "Two Little Boys" and Benny Hill's "Ernie". He was known as a technological innovator, pioneering the use of the talkbox.
Sullivan built his network of connections after being hired by Wilde at the 2 I's Coffee Bar in London to join his backing band, The Wildcats, who appeared on impresario Jack Good's TV show "Oh Boy". He was later the house guitarist on "Top Of The Pops" and "Ready Steady Go", and gave guitar lessons on the Bay City Rollers' series "Shang A Lang".
By the 1980s he had moved into ad jingles and film music, and in recent years toured as the BJS Duo with guitarist Doug Pruden. Earlier this year he was filmed for a documentary about pop producer Joe Meek.
He recently said: "My whole life is geared to play guitar. I play what I want when I want - and I hope the listener gets as much pleasure as I get. I'm a very lucky man: I'm living my life with my hobby as my profession".
Blackmore once said of him: "Big Jim was a big influence. He'd only been playing about two years, but he was just about the best guitarist in England, straight away. I thought I was alright and learning pretty well. I couldn't even understand what he was doing".