With Steve Winwood as lead vocalist, the band had two No. 1 United Kingdom singles - Keep on Running in 1965 and Somebody Help Me in 1966 - and seven British Top 40 hits before Winwood departed in 1967, soon to form Rock and Roll Hall of Fame band Traffic.
Winwood eventually left the band to form Traffic in 1967, but the Spencer Davis Group carried on without him, though with far less success. "We met and the seeds of the Spencer Davis ensemble were sown".
In 1963, Davis formed the self-titled The Spencer Davis Group after persuading established jazz artists Muff and Steve Windwood to join him and friend Pete York on the passion project. The Winwood brothers split in 1967, but Davis reformed his band and continued into the "70s". I already have a big brother, he affected me a lot, and Spencer became like a big brother to me at the time. He influenced my tastes in music, and he owned the first 12-string guitar I ever saw. "He was a highly ethical, very talented, good-hearted, extremely intelligent, generous man".
The most famous former member of the Spencer Davis Group has spoken about Davis's passing.
According to the official charts company, the band has topped the United Kingdom singles chart twice, with hugely successful Keep On Running and Somebody Help Me, and have seven of the top 40 singles and three albums from the top 10.
Influenced by the burgeoning British blues and skiffle scenes, he performed in bands with future stars including the Rolling Stones' Bill Wyman and Christine Perfect - later Fleetwood Mac's Christine McVie.
Music by The Spencer Davis Group is also included in the recent Helen Reddy biopic I Am Woman. He worked with acts including Bob Marley and Robert Palmer, as well as helping to launch Winwood's successful solo career.
Davis is survived by his three children and five grand-children.