Steve Winwood backed visiting US blues players when he was 14

Last month I suggested that having a father who played jazz and singing in a church choir were key experiences for the British Invasion generation of musicians.

One of the examples of people with this background I gave was, inevitably for this blog, Steve Winwood.

Chris Blackwell, the founder of Island Records, was the man who signed the Spencer Davis Group. In his memoirs he gives an account of Winwood's musical background that fills out my theories - and he adds something intriguing:

Steve and his brother Muff, older by five years, had grown up with music, playing in their father's jazz group in Birmingham pubs near their house. Steve had started out learning '30s and '40s dance music to play with his dad and he was a High Anglican chorister as well; so, when skiffle and early rock and roll came along, he was only ten, but already taking to this new music and to the new soul sound of Roy Charles as a highly skilled, technically very adept and versatile musician. By the time Steve was fourteen, he was playing in pick-up bands for visiting blues players like Sonny Boy Williamson and Memphis Slim.

I would like to know more about these pick-up bands and which other future British greats were involved. I know that sometimes established bands like the Animals or the Spencer Davis Group got the job of backing these American blues greats, but the pick-up bands are somehow more intriguing.