Walker's fan club membership had at one stage exceeded that of the Beatles.
By 1969 he had established himself as a songwriter, broken new ground with three highly original and acclaimed solo albums, sung a handful of film themes and developed a growing reputation as a record producer.
All this followed his phenomenal success as lead singer of the Walker Brothers who, in between unleashing a storm of teen hysteria in the mid-1960s, issued three classic singles and a trilogy of memorable albums.
Above all, Walker will be remembered for a golden baritone which could convey sadness, heartbreak, mystery, yearning and joy in equal measure. But the hit albums dried up and stage nerves eventually put paid to his live performances.
In 1984 he ended his self-imposed exile from the recording scene with the release of the critically acclaimed Climate of Hunter. Its commercial failure prompted Walker to draw back from the music industry.
In 2012 Walker released his 14th solo studio album, the critically acclaimed Bish Bosch.
Thom Yorke of Radiohead tweeted his sadness at Walker's death. "He was a huge influence on Radiohead and myself."
Walker is survived by partner Beverly, daughter Lee and granddaughter Emmi-Lee.
- AP, Telegraph Group Ltd